Guide to the aquarium of the Zoological Station at Naples

GIFT OF

- '-.cms— o^
-

GUIDE

TO THE

AQUARIUM

OF THE

ZOOLOGICAL STATION

AT

NAPLES

NAPLES

PUBLISHED BY H. DETKEN
Piazza Plebiscite and Via Roma 288

\

STAB. TIT. DELL UNIONE.

The little book which we here offer to our visitors, is inten-
ded to answer, in an easily comprehensible manner, the que-
stions which experience has proved are the first to be put.

These questions partly relate to the novelty of the animal-
world exhibited, which is not to be found in other Aquariums,
especially those in the north ; and partly originate in the tra-
ditions which an earlier stage of science has left lingering in
the minds of the uninitiated, without reconciling them with the
.new, and not therefore always lucid, conceptions of those problems
and theories which, the substance and result of a scientific re-
volution of extrordinary extent, are being ever more spread
abroad by popular literature. We have done our best to avoid
wearying the reader with the elementary explanations that too
often increase the bulk of such guides as this.

The Aquarium of the Zool. Station has for years enjoyed a
good name, owing, chiefly, to the circumstance that it is situa-
ted in the shores of the richest in animal life of all European
seas. This wealth of marine Fauna is reflected in the tanks of
the Aquarium, the contents of which often vary, according to
the season and the influence of the weather in the fishing. No
doubt there exist many much more luxuriously appointed Aqua-
riums in the north, which surprise the visitor by their deco-
rative .architecture or beautiful grottoes , but they are like
portraits the want of interest in which is compensated for by
magnificent accessories, such as velvet dresses, costly furs, and
gorgeous frames. %

Our Zool. Station is able to dispense with all such pomp,
and this is done gladly, in order to use all its available means
for the purely scientific aims in aid of which alone it was cal-
led into existence.

In conclusion, I beg the reader to note the following pre-
liminary remarks by R. Schmidtlein , the special director of
the Aquarium, and author of the guide, for they will facilitate
the understanding of the subsequent descriptions.

ANTON DOHRN

244738

PRELIMINARY REMARKS.

Not being able , because of the free combinations
and constant changes among the animals in the
Aquarium, to describe tank by tank in the order in-
which they stand, we have rather chosen to follow,
in a general way, the arrangement of the zoological
system, and beg the reader to guide himself with
the help of the drawings affixed to the walls of th'e
tanks.

These drawings are provided not only with the
scientific Latin name of the animals represented,
but also with the common names in the modern
languages, and each is marked with the number of
the page of this guide in which the description of
the animal in question is to be found.

RICHARD SCHMIDTLEIN.

Sponges (Spongiae).

For a long time it was doubtful whether these creatures ,
which, in their fully developed state, are firmly fixed and see-
mingly immoveable, were plants or animals. Late research has
finally shown that sponges are animals, and that their resem-
blance to plants depends upon a few entirely superficial cha-
racteristics.

Sponges consist of an inner fibrous skeleton, surrounded and
hidden by a living body of a gelatinous substance. The skele-
ton is secreted from the gelatinous mass, and consists either of
a web of elastic horny fibres (the Bath-sponge and correlati-
ves) , or of innumerable microscopic formations of a determi-
ned shape (calcareous sponges) which compose the skeleton ;
these shapes vary in a wonderful manner, and are very orna-
mental, resembling anchors , stars , balls , hooks , cylinders ,
and so on.

Each species of sponge is distinguished by the shapes of the
particles that form the skeleton, and therefore the special study
of these shapes is of great importance in the systematication
of sponges.

The sponge best known to the unscientific, the common lath-
sponge Euspongia, has, when the animal is alive, a very different
.appearance to that which it bears when brought to market. The
•mass of elastic horny fibre with which we wash ourselves is
really only the skeleton of the sponge, and is, in the living
animal, covered by a soft jelly-like substance. This substance
contains a large quantity of pores which can open and shut ,
allowing the sea-water to flow into the body of the sponge in
all directions. The water is kept flowing through these chan-
nels by the action of ciliated hairs, and leaves them by fewer
but larger openings. The infusoria and other small organisms
^contained in the water are retained and absorbed as nourishment
by the inner cells of the animal.

- 6 -

Rocky coasts and coral reefs are the chief "liabitat of the
sponges ; a few kinds prefer to settle on some other animal.
If a sponge be cut into pieces, each piece is still capable of
living, and developing into a perfect individual; a capacity of
which a very practical use is made by cultivators of the bath-
sponge. These sponges are found in all parts of the Mediter-
ranean, and also in the Gulf of Naples. To prepare them for
the market it is only necessary to wash and squeeze them,.
by which process the sponge-cells , that is the really vital
part, are destroyed. The finest and most costly bath-sponges are
those from the Levant, and are met with chiefly on the coasts
of Asia Minor. In 1862, the best were sold wholesale by weight
at prices varying from 100 to 150 francs per pound upwards; other
kinds, like the so called Zimocca sponge, are worth only the tenth
part of that sum ; these are generally found on the coast of
Greece. The third kind, the horse-sponge, is seen in the market
in very large pieces , often measuring a foot and a half. They
are chiefly found on the African coast. Sponges from Italy and
Dalmatia are also brought to market. Professor Oscar Schmidt
says : " These sponges are found from the Quarnero to the Ionian
Islands, at a depth of about 20 to 120 feet. The bath-sponge
seems particularly to favour the coasts and cliffs, but not the
enclosed harbours. Its favorite spot is a steep and rocky coast,
and it is seldom met with at a distance from the shore. Sponge-
fishing is the exclusive occupation of the male inhabitants of the
small island of Crapano. In spring the fishermen go out in
pairs in strong open boats to fish, which is a very troublesome
business. One man propels the boat slowly forward, while the
other stretches his whole body over the bows looking for
sponges at the bottom of the sea. If a light breeze ruffles the
surface, oil is poured upon it to smooth it. The fisher is ar-
med with a long elastic spear , and with this, when he has
got as nearly above it as possible, he loosens the sponge. The
sponges are kneaded and squeezed out while quite fresh, and
after two or three days the operation is repeated , the cells
having then begun to decay. But instead of bringing these
clean sponges to market, the Crapanese and other fishermen
fill them with fine sand to increase the weight about 90 per
cent. Buyers are naturally up to this trick, and it is of no avail,
but the beating out of the sand wastes much time in the wa-
rehouses, and we all know that the first thing -to do with a
newly bought sponge is to continue the operation commenced
in the maritime towns ".

Besides the bath-sponge, the Aquarium contains many spe-
cimens of sponges , which attract attention by their vivid
colours and various shapes. We will specially mention the splen-
did orange-red bunches of the Axinella and Myxilla, the cups
of the Reniera calyx, the sulphur-yellow balls of the Tethya,
and the branching coral-like colonies of the Clathria.

The calcareous sponges are usually small and unsightly; the
largest species found in the gulf is the Leucandra aspe-
ra, with white pipe-shaped individuals united on one stock.

One of the many advantages of the Aquarium of the Zoologi-
cal Station is that of being able to introduce to its visitors
living sponges. Their surroundings in the Aquarium so nearly
resemble natural conditions, that not only is it possible to tran-
sport the living sponges thither from the sea, but, during the
course of years, various species have settled on the rocky sides
of the tanks and nourish there to perfection , thus facilitating
their study to zoologists.

Polypes (Anthozod).

If it is strange to the uninitiated to hear animals called spon-
ges, which, wrhen seen alive, have nothing of a spongy appea-
rance, he will be no less astonished, when he learns that the
word « coral » means something else besides the beautiful red
or white branches which are often seen adorning a chimney-
piece or a writing-desk. And yet such branches are not the
real animals , but only the framework which they construct
for themselves, and in which they live side by side, or one over
the other, by hundreds and thousands. Of the real coral ani-
mal, scientifically called polype — those polypes give the best idea
which are always the chief ornament of northern aquariums, the

Actiniae or Sea-anemone*.

In looking at these animals, we see a cylindrical column, the
base of which is fixed to some other object, and the upper end
of which is crowned with numerous and extremely mobile ten-
tacles.

In the middle of this crown of tentacles there is an easily
recognisable opening , which is both the mouth and the anus
of the animal. This opening leads into a sort of wide sack, sur-
rounded by the muscular walls of the body, in which the food
is digested. At first sight it seems as if the soft naked body of

- 8 -

the polype were sadly in need of protection , but that is not
the case ; it possesses excellent weapons of defence. In many
parts of the body, but chiefly on the tentacles which serve to
catch the prey, there are numerous microscopic blisters , the
so-called nettle-cells, each of which contains an acrid fluid and
spirally rolled up filaments. When the animal comes in con-
tact with an enemy or its prey , it darts out some hundreds
of such nettle-filaments, and the fluid which issues from them
at the same moment has a benumbing and even deadly effect
on many of the smaller organisms. The Actiniae, most highly
organised of polypes, are uncommonly greedy, and devour not
only the bits of meat given it, but catch all the living worms ,
crabs, snails and fishes that come within their reach. An acti-
nia, a Sagartia parasitica, caught and devoured an octopus
much larger than itself. A large Anthea caught and con-
sumed a shark above a foot long. The extraordinary tenacity of
life in the Actiniae very much facilitates their preservation in
the tanks ; in many cases we have kept the same individual
alive for years. One lived, it is said, for more than forty years
in a small aquarium at Edinburgh , and during that period
brought forth above a thousand young ones.

Among the numerous beautifully coloured kinds we notice
the Anthea cereus, so often found in the Gulf of Naples ,
examples of which are seen clustered together on a rock like
flowers on a bed.

Still more splendid than this Anemone , which has hitherto
been found only in the Gulf of Naples, is the remarkable Cla-
dactis Costae. This animal lives at a considerable depth. At
first we could not succeed in keeping it alive in the Aqua-
rium , but since the last few years the examples taken live
for many months. In its expanded state the Cladactis is cer-
tainly one of the most beautiful of sea-anemones. The Sagar-
tia is interesting from its habits; it lives on the shell of the
Hermit-crab, and allows its host to carry it about. The Acti-
nia Mesembryanthemum is often eaten in Naples, and the
Anthea also.

After examining the Actiniae it is easier to understand the
structure of the true corals. If the Actiniae were capable of se-
creting an outer or inner calcareous skeleton , that skeleton,
after death, would be valued, like a coral » , as an ornamental
substance. The beautiful orange-coloured Astroides, which co-
vers the rocks of the Aquarium, is such an Actinia with a ske-
leton. Its true form can only be seen when the sky is over-

- 9 -

cast; under such circumstances it erects its body often to the
extent of more than a centimetre, its beautiful crown of tenta-
cles unfolds, and when thousands of these animals are close to-
gether and all expanded, they look like a precious orange-co-
loured velvet carpet. But when the sky is bright, they draw
in their tentacles, shrink up and look very insignificant. Even
when expanded there is nothing to be seen of their skeleton;
it is only when they are dead and decayed that it becomes
visible, shaped like a honeycomb , the cells of which are filled
with radiating partitions. An attentive observer will find these
whitish skeletons here and there in the tanks.

Many parts on the coasts of Italy are covered by this coral,
and anyone who makes the beautiful trip from Amalfi to Sca-
ricatoio in a boat will see the rocks covered just below the
water-line with these yellow creatures. The mighty reefs or
atolls found in tropical seas are formed of similar corals, and
are often many miles in extent and hundreds of fathoms thick.
The colour of these reefs is most beautiful.

The branches of the coral are produced by certain peculiar
propagating processes, scientifically distinguished as partition
and budding. In the process of partition an organism splits in-
to two or more parts , each of which develops into a perfect
animal. The process has been often observed and even artificially
induced by cutting a living animal into several pieces. These
grow and each gradually becomes an entire polype. A similar
thing happens with the coral polypes, but with this important
difference, that the partition (natural , not induced) does not
extend quite to the base of the animal, but the divided parts
remain connected at a certain point. They secrete a calcareous
substance which naturally remains connected , and thus , in
the course of centuries, are formed those immense coral reefs
or islands mentioned above. The second and more rapid pro-
cess is budding. In this operation the generating organism re-
mains intact, but at one part of it there commences a process
of growth by which a second organism is produced , which ,
however, in the corals, does not separate from the first, but
remains connected with the parent organism. Now all these
organs are partly supported, partly enveloped, by the varico-
loured calcareous skeleton which they themselves have secre-
ted, and which often look like trees or large fungi — such as
one sees on the bark of real trees, — or like bushes. But of wha-
tever shape or colour they may be, it must always be remem-
bered that these skeletons are not the animals themselves, but

- 10 -

only their Jiouse, in the building of which millions of tiny po-
lypes have taken part; while hundreds and thousands have al-
ready died, and their descendents at this day stretch forth their
tender prehensile arms, like little brushes or tiny feathery
crowns, from the pores of the coral tree.

The precious coral Corallium rubrum , the universally
known species of this group, owes its great value to its beau-
tiful colour and capability of being highly polished , its stony
axis - skeleton being hard as marble. The ancients prized it
highly, but they had an entirely mistaken idea of its nature -
shared even now by very many people, — according to which
the precious coral was a plant which was soft and pliable when
left in the sea , but became hard as stone when taken out.
Careful study has made us fully acquainted with the coarser
and finer construction, as well as with the habits and propa-
gation of the precious coral polype, and we know that the stony
substance in the form of beautiful branches and twigs, is the
product of the coral polypes, which have secreted it as the com-
mon support and skeleton of their soft vital parts. If we examine
a newly taken and living branch of coral, we find this calcareous
substance covered by a softer equally red rind, just as the trunk
of a real tree is covered by the bark; and if the coral-branch is
carefully hung in a large vessel of sea- water, we shall see, in
a short time, the little coral animals, like delicate white flower-
cups with eight feathery leaves, unfolding themselves at innu-
merable points on the surface of the branch. Each of these ani-
mals has the before-described structure of a polype, and is vi-
tally connected with all the other individuals by canals of nou-
rishment which intersect the rind in all directions. This rind,
like the stem, is also secreted by the animal, and consists of
innumerable microscopic calcareous particles like thorns. The in-
timate blending of these particles, which are deposited in strata,
produces the stem. This structure at once distinguishes the true-
coral from all imitations.

The precious coral propagates by eggs and budding. There are
male and female stocks, as well as stocks that carry individuals
of each sex; and even hermaphrodites (male and female in one
individual) have been observed. In the egg, while yet in the
parent-body, is developed a longish pear-shaped larva, which
at first swims freely about, but presently attaches itself by one
end of its body to some rock, and develops into a coral polype,
which in its turn begets other individuals by budding , and
thus a new stock is commenced.

- 11 -

The precious coral is found in the Mediterranean Sea. It grows
on rocky ground in the neighbourhood of the coasts at a depth
of about 240 to 600 feet, seldom beyond that region; and is
principally fished on the coasts of Sicily, the Jonian islands ,
Algiers and Tunis ; the last place alone yearly yielding about
60,000 pounds weight of coral, at a value of about two mil-
lion francs. The apparatus for fishing coral consists of a heavy
cross of wood attached to a windlass, and hung with old nets,
unravelled ends of rope, and such like. This is dragged along
the bottom of the sea, when the jagged branches of coral are
caught in the meshes, torn off the rocks, and rise to the surface
entangled in the nets. Before working the coral into ornaments,
the branches are brushed in order to get rid of the rind with
the animals; afterwards the surface of the stem is filed off, and
the reddish dust thus produced is sold under the name of co-
ralline, and used as tooth-and polishing powder. When the co-
ral has been thus prepared it is polished with emery paper and
oil; the beads are turned in a lathe and bored, and figuies are
worked with the graver.

The value of coral varies greatly, even in the raw material.
The larger and thicker branches are often injured by boring ani-
mals (worms, sponges) and their value varies from three to ten
francs a pound. Commonly good material fetches from twenty
to forty francs, the selected rose coloured coral from two to
three hundred francs a pound. Black coral is the precious co-
ral chemically altered by the action of muddy deposits.

A very beautiful coral may often be seen alive in the Aqua-
rium; it is the Dendrophyllia, the skeleton of which consists-
of pure white chalk, and is formed of large branches. The po-
lypes are of a brilliant yellow colour and are crowned when ex-
panded with lovely tentacles. This kind is often met with in
the Gulf.

Besides the above-mentioned calcareous corals, there may be
seen alive in the tanks some horny corals, fhe Antipathes and
Gorgonidae, which have a flexible horny skeleton. The little
trees of the Gorgonidae are vertically branched, which is seen
by the direction of the tiny feathers which protrude at regu-
lar intervals on both sides of the branch when the polyps ex-
pand their tentacles. It is exactly these little feathery brushes
that are the living animal. There are white, yellow, and red
Gorgonidae, most of the yellow kind are found in the Gulf ; f
Naples. Then there are the remarkable Alcyoniae , or cork-
polypes, which have no solid skeleton at all, and are theieforo

- 12 -

capable of great increase of volume when filled with water. An
Alcyonia which, when contracted, looks like a piece of red or
yellow sponge, is scarcely to be recognised when fully distend-
ed. It is then three or four times its original size, becomes al-
most transparent and unsubstantial, and is covered with polypes
that look like tiny transparent flowers.

Almost still more beautiful are the coral colonies called Pen-
natulae or Sea- feathers, which can also expand and contract
at will. In the last state they look very ugly, like some shrunken
dead creature. But at other times they are distended to tran-
sparent beauty, standing erect, with all their wing or leaf-like
appendages studded on their upper edges with charming polypes,
the tentacles of which may often be observed in motion.

The Virgularia or Sea-rod , belongs to the same family,
but its polypes are not attached to such leaf-like appendages.
The Pennatulae can move freely about, and bore their fleshy
extremities into the sand, an operation which may sometimes
be observed in the Aquarium.

Iledusac (Jelly-fish)

Any one who has visited northern coasts and remembers ha-
ving often seen ugly jelly-like lumps lying on the strand, looking
still more disgusting because of the coloured -stripes that cross
them, will scarcely believe it, when he sees swimming about
in the Aquarium, and is told that they are those very lumps,
the large medusae Rhizostoma and Cassiopeia, or the smal-
ler forms of the Pelagia, Oceania, Geryonia, and Cunina.
These living medusae make a very different impression to that
excited by the ugly dead jelly-fish. Their almost total transpa-
rency , beautiful motions , and often splendid colours attract
every eye. But on looking at these « animals » the visitor must
somewhat limit his idea of what an animal consists of. The
Medusae which are nearly related to the polypes have just as
little as the latter anything that is like a head, arms or legs.
They are merely a sort of shallow reversed cup, not unlike an o-
pen umbrella or a mushroom, and move by therythmic contractions
of their gelatinous body. On the edge of the cup are the organs
of sight and hearing, and it is generally also surrounded by a
nerve-ring. From the centre of the hollow of the cup hangs a
long gelatinous transparent stem which is hollow and provided
with a mouth orifice. This stem ortrunkis sometimes— for example
in the Cassiopeia and Rhizostoma— very broad and consists

- 13 -

of a number of smaller tubes, each of which contains an open-
ing which leads into the common hollow or stomach. From
the rim of the cup, which is often zigzagged, there hang long
filaments, which the animal can extend or contract at will. They
are frequently of great length and when the medusa swims
float gracefully behind. They are furnished with numerous nettle-
cells such as we saw in the actiniae. They are equally a
capital protection for the delicate bodies of the medusae. The
disagreable burning sensation we often experience while ba-
thing in the sea , proceeds often from our having come into
contact with a medusa, and the effect is sufficient to kill small
organisms. Some oceanic medusae , which attain a size of 30
to 60 centimetres, and a weight of 50 to 60 pounds, are even
dangerous to man. The rowing of the medusae is a very in-
teresting fact. At certain periods enormous quantities of these
creatures collect together and commence their travels ; ships
are often delayed for hours and even days by meeting these
swarms. The animals are so close together that a stick thrust
among them remains in an upright position, as if stack in the
mud, and ordinary rowing-boats can scarcely force a passage.
Such emigrations are probably the result of over-population by
these creatures of a certain ocean-district, and consequent want
of food ; perhaps also of climatic influences ; the small troops
that not rarely appear on the coasts and in the bays, are, in
all probability, connected with the peculiar process of propa-
gation observed in many medusae and known as alternation-of-
generation.

This process, first discovered by the German poet Adalbert
von Chamisso, while studying salpae during a cruise round
the world, has since been enounced as an important scientific
theory by the Danish naturalist Steenstrup. It consist chiefly
in the following changes: an animal which we will call A pro-
pagates, but the young it produces do not resemble their pa-
rent at all, but are quite different animals which we will call
B\ B propagates, and again its young are not like itself, but
like A. In other words: in order that A can propagate A, an
intermediate number B is necessary.

In the case of many medusae — not in all — this intermediate
member appears in the form of a creature scientifically known
under the name of a Hydroid-polype, which looks exactly like
a plant, very similar to a coral stock. The aquarium sometimes
contains the Tubularia, Campanularia. and Sertularia,
all representatives of the Hydroid-polypes. They come from the

- u -

egg of the medusae, are propMgated by partition and budding,
and so, like the corals, form larger or smaller colonies. At a
•certain time they develop buds which fall off the parent stock,
and swim about as medusae , in their turn laying eggs from
which issue polypes. The Hydroid polypes are found in immense
quantities on rocky coasts amongst the sea-weed. These colonies
feed on still smaller animals, such as crabs, worms, infusoria
or larvae, which, come within reach of their tentacles and are
benumbed by the nettle-cells.

SipBioiiopliorcs or Siphon jelly Gsli.

These most wonderful of all sea .creatures are equally the
delight and despair of the naturalist. Their fragility, for their
bodies break at the slighest touch, is as great as the beauty
and originality of their structure. They swim, like the medu-
sae , during calm warm weather . close to the surface of the
water , and are immediatly seen by the practised eye of the
zoologically educated fisherman, who carefully catches them in
glasses held for them to swim into. In this glass they are care-
fully carried to the Aquarium and as carefully emptied into
the tank, and so we can often boast of specimens of the A-
galmopsis, Physophora, Forskalia, Praya, Apolemia,
Athorybia, Hippopodius, Physalia, Velella, and others.

The Siphonophores are held by most naturalists to be wan-
dering colonies, that is, creatures that consist of more than one
organism and are yet a unity. Individuals of the same species
living in one colony or stock in more or less intimate connection
is a very common phenomenon in the animal kingdom; coral
polypes afford an example on a large scale. But the case is rather
different with the Siphonophores; they are no longer uniformly
organized individuals, each of which performs the same func-
tions and so is capable , in a certain sense , of independent
existence ; bus the Siphonophore colonies are composed of ve-
ry differently formed (polymorphous) individuals, animals that
divide amongst them the different offices of the colony and so
represent an organically connected whole, or an organism of a
higher order. Polype-like eaters provide for nourishment, me-
dusa-like swimming-bells render possible a change of place, and
real medusae undertake the business of propagation; in short,
there is similar « division of labour » as that found among ants
and bees, with this difference, that in the case of these insects
the polymorphous individuals lead isolated existences, while, in
the Siphonophores, they are inseparably united.

- 15 -

The polypestock of the beautiful Velella, or sail-siphonophore,
forms a cartilaginous ball, on the underside of which sit the
single individuals, while on the upper side is a thing like a
sail, which aids the progress of the colony swimming close to
the surface of the water.

Ctcnophores or Bib-jcllyGsli.

The Ctenophores are as transparent as the medusae, a quality
possessed by many marine animals. There are very many trans-
parent mollusks, and even transparent worms, crabs and fish,
as we shall see later. The reason of this property is probably
to be sought in the protection it affords to these animals ,
the ease with which they can both avoid their enemies and
catch their prey. For all these delicate creatures are cruel
robbers, and devour animals the very contact with which we
should think would be sufficient to annihilate them. But their
terrible nettle-cells enable polypes and medusae to kill much
larger animals than themselves, and one may very often see
a small fish in the stomach of the « delicate a medusa, which
completely dissolves and digests it.

The shape of the Beroe and Cydippe (both Ctengplwres) is
like a barrel, the long remarkable Venus-girdle (Cestus Ve-
neris) is like a ribbon. These three species are often found
in the tanks , and attract the attention of the visitor by the
rainbow-coloured waves that seem to run along their bodies.
These waves of colour are produced by rows of very delicate
oar-plates that lie in great numbers close together , and are
almost constantly in rapid motion, which breaks the rays of
light and causes the appearance of the prismatic colour.

The zoological Station may well be proud of its exhibition
of the marine animals now mentioned. The southern position
of Naples and the situation of the Aquarium close to the sea,
give the latter this valuable monopoly. Succesive days of calm
and fine weather during spring and autumn enable the fisherman
to catch these rare and beautiful animals. They die, however,
very soon, the Sinophophores especially scarcely lasting a day.

The animals hitheito mentioned are scientifically classed
under one type , which bears different names, but is oftenest
described under that of the Coelenterata given by Professor
Leuckart.

The animals we shall now describe used to be included with
them under the common name of Radiata, but later research
has proved that they are very different. These are the

- 16 -

Echiuoderius or Sea-urchin*.

To this class belong sea-urchins, starfish, seacucumbers and
sea-lilies. It is saying very little when we call them interesting
and remarkable, all animals are so, even the sparrow and the
common fly, but one must be possessed of various and correct
knowledge in order to find it out. The Echinoderms however, are
doubly interesting to people who live at a distance from the
sea, for nothing like them is to be found either on land or in
sweet water; they are entirely novel creatures , true children
of the ocean. But this is not the most interesting fact concerning
them.

Another peculiarity distinguishes the Echinoderms from all
wellknown land and sweet-water animals. It is true that these
land creatures are as mysterious and inaccessible to the unlear-
ned, as far as concerns their organisation, as any marine snail,
medusa or sea-urchin. But on the whole, the unlearned know
that all birds, fish and insects can boast of a head, legs, gills
or wings, eyes, mouth and many other visible organs.

But what must we think of a sea-urchin or starfish? These
creatures live, therefore they must eat; but where is their mouth?
Where are the members with which they seize their food? They
live in the sea, -but how do they move? Do they swim or creep?
Can they see and hear ?

The unlearned cannot answer these questions, and will be
grateful, if, without superfluous science, this little book tries
to explain the essential properties of the Echinoderms.

First of all , we beg our reader to put out of his head all
such things as heads and tails, arms and legs, gills and wings;
and to be sure that the Echinoderms can do without these mem-
bers quite as well as the corals or medusae. But the Echino-
derms have a much more complicated organisation than any
of these last - named creatures.

It is only lately that we have become acquainted with the
anatomy of the Echinus and, as usual, the better it is known
the more interesting the object becomes.

The outer forms of the Echinoderms vary greatly, Some are
as round as a ball, others flat as a leaf; others again are like a
star or a sausage , or , to use a more refined comparison, a
cylinder; and finally, some have a stem like a flower and see-
mingly a calyx and leaves. The shell or skin of these animals
looks like mosaic. It consists of a great number of differently

- 17 -

sized but regularly disposed calcareous plates. In the Sea-ur-
chin (Echinus) these plates are joined so that the whole body
seems to be in one piece. In the Starfish (Asteridae), on the
contrary, they are more loosely connected and permit motion,
and the Starfish can move its arms up and down as well as
sideways. This fact is seen best when the animal is on its
back and wants to turn over. ( The keeper will induce this
movement at the visitor's request).

The Brittle-stars (Ophiuridae) are so made that their single
arm constantly moves like a snake, and the Feather-stars (Com-
atulae) can even swim by lashing their long arms. But the
skin or shell of the Sea-cucumbers Holothuridae) has no such
calcareous mosaic; it is like a piece of leather dotted at intervals
with strangely formed calcareous bits, like anchors , stars and
rosettes, so that the skin is very elastic, allowing the animal to
stretch and bend its body in all directions. This construction
of the skin, however, can scarcely be seen, so covered is it with
spines and other appendages. The tiny calcareous plates of the
starfish are also not easy to be distinguished, but in dead
examples, which the keeper has at hand, we perceive their enor-
mous number, amounting, in some of the large individuals, to
a hundred thousand!

You will ask how the Sea-urchins and Starfish move in the
water, since they have no legs, and cannot, like worms, and
eels, creep or swim by the undulating movements of the whole
body ? Before we answer this question we beg the reader to
examine carefully one of these animals, which he will certainly
find either sticking to the glass of the tank, lying on the sand,
or climbing on the rocks.

On the side turned to the glass (in the first case) he will
see a great number of small transparent tubes, provided at the
end with a sucking- disk. These tubes or tentacles are extremely
flexible, can stretch and contract like worms, and adhere to
any object. They are called sucking- feet , and are connected
with a system of water pipes, consisting of a circular channel
with branching arms, lying in the central disk of the animal.
Each arm has two canals, which are studded with sucking-feet
like the leaves on a stalk, and through these canals the sucking-
feet are filled with water. The water is received through a
sieve-like calcareous plate on the animal' s back fmadrepore-
plate) and is pressed by the contraction of the canals into the
sucking-feet. By this alternate expansion, contraction and adhe-
sion the animal pushes itself along on its base.

2

- 18 -

Such are the general organs of locomotion of the Echinoderrns,
for the Sea-urchins and most Sea-cucumbers move in the same
manner, only, because of their different shape, the sucking-feet of
the Sea-urchins are spread over the whole body in five rows,
while in the Sea-cucumbers they are otherwise disposed.

The sucking-feet of the Sea-urchin have another very important
use, which may often be seen in action in the aquarium. They
enable the animal to catch its prey. When an animal which
the Sea-urchin can eat comes near,, the latter stretches out
a few of its tentacles or sucking-feet until they seize the prey.
If the victim is not immediatly aware of the attack, it is lost,
for other tentacles quickly follow, and the Sea-urchin gradually
pushes its whole body close to its prey, which is soon bound
fast by hundreds of tiny fetters and brought to the vicinity of
its enemy's mouth. All efforts to escape are in vain, for even
if some of the sucking-feet are torn, others take their place.
So the victim soon resigns itself to its fate , and is slowly
dissolved and digested.

The mouth of the Sea.-urchin, like that of the Starfish, is on
the underside of its body. Many Sea-urchins have very com-
plicated masticatory organs, which are situated in the interior
of its body, and enable it to grind even very hard objects. All
the Echinoderms in the Aquarium possess these organs. Other
kinds live in the sand, which they swallow, digesting the organic
matter therein contained and then expelling the useless re-
mainder.

Starfish have no masticatory organs, but the membrane of
their intestine secretes such an acrid fluid that it kills the
animals they have swallowed, such as shell-fish and snails, fre-
quently also fishes and crabs. The Starfish approaches some
animal lying quietly at the bottom of the water, and catches
hold of it with its sucking-feet so suddenly that it cannot
escape. Starfish are really distinctive animals, and ought to be
destroyed in the interests of fishing.

Most of the Sea-cucumbers (Holothuridae) nourish themsel-
ves by taking up sand and mud and assimilating what organic
matter they may contain. Others act in a different manner ,
seldom creeping about, and generally remaining quietly attached
to some stone or other object. They then expand their large
many-branched tentacles, which are filled with water, and insert
them alternately into their mouths.

The Echinodermata are divided into the four classes we have
mentioned:

- 19 -

1. The Sea-lilies (Crinoidea), 2. the Starfish (Asteroidea),
3. the Sea-urchins (Eehinoidea),4. the Sea-cucumbers (Holo-
thuroidea).

Of the first class the Aquarium possesses the Comatula
mediterranea, a very beautiful creature, which varies much
in colour. Straw-coloured, orange, blood-red and brown-and-
white examples may often be seen in great quantities in the
tanks. They generally adhere to corals or annelids, so that
they look almost like gay flowers springing up in various places.

The Aquarium has a great number of Starfish. There are
the Asteracanthion, Astropecten, Luidia, etc. Some of
these creatures, for example the Ophidiaster, are found on
close inspection to be very beautiful, being not only brilliant
in colour, but having beautifully marked skins.

The Brittle- starfish or Ophiuridea are numerously repre-
sented; but they do not so much attract the attention of the un-
learned: Ophioderma longicauda, etc.

The Sea-urchins, on the contrary, are very striking. Above
all the Echinus melo is remarkable for its light flesh tint,
and size. The Echinus liyidus and kindred are eaten, that
is, the shell is opened and the bright yellow ovaries are taken
out and eaten like oysters. The Toxopneustes brevispinus
is of a very beautiful violet-brown colour, and the Dorocida-
ris hystrix is distinguished by its few but large and strong
spines.

Sea-cucumbers are numerous in the gulf of Naples, and the
Aquarium can show more than six different species, some in
great quantities, especially the large Holothuria tubulosa,
an immense Sea-cucumber of a brown colour, more than a foot
long. Another remarkable Holothuria is the H. regalis, the
body of which is not round, but square and flat. These Holo-
thuridae are remarkable for a circumstance to which we will
now draw your attention. In the body of these creatures is
often found alive a beautiful I little fish, about 20 centimeters
long, the Fierasfer acus, which sometimes protrudes its head
from the anus of its host. It lives on small crabs, to catch
which it must leave its curious quarters.

Certain Holothuridae are eaten, especially by the Chinese;
the so-called Trepang is the body of the Holothuria edulis
emptied of the intestines and dried in the sun or by artificial
heat. Thousands of Malays and Chinese are occupied in fishing
and drying this food, which European palates find can only be
eaten when strongly spiced. Whole fleets of boats sail annually

- 20 -

for the coral-islands between Xew Holland and New Guinea^
in the bays of which the animals are found abundantly.

Worms or .4 11 lie! Ids.

Many people dislike the mention of a worm. This is not only
owing to the traditional repugnance felt by educated persons
for many of the lower animals, but also to the fact that the
habits and resort of the few species known to non-scientific
people are disagreable. Dusty earth-worms, bloodthirsty leeches,
tapeworms, trichines, such are the creatures generally thought
of when worms are mentioned, leaving out the serpents, snakes ,
caterpillars, and other repulsive creatures often included in
the list.

But in the sea there live a quantity of worms belonging to
the very same genus as the despised earth-worm: namely, the
Annelids, or marine worms , which, in delicacy of form and
beauty of colour, are in no way inferior to the anemones or
other beautiful inhabitants of the sea. The reader will find this
statement confirmed on casting a glance at the annelid-tank
in the Aquarium, which rather resembles a garden planted with
miniature, beautifully-coloured palmtrees than a collection of
a worms. » There , on slender stems , wave feathery spiral
crowns belonging to the Spirographis; there the Protula
shoots forth *bright,- red tassels of a similar form from a white
calcareous tube; while in another place a confused mass of such
tubes seems set with hundreds of many-coloured little brushes,
all as delicate as flowers, reminding one more of the children of
the goddess Flora than of animal-forms. And yet all these crea-
tures are real worms, which have built these leathery or calca-
reous tubes for the protection of their soft bodies, and the above
mentioned feathery palm-like crowns springing from their hei-ds-
are the membranes of their gills. Touch one of these tiny crowns
ever so slightly, and it will instantly disappear into the tube;
the worm has returned into its shell, with which it is in no
place actually connected, and waits a little until the supposed
danger has passed. Then, slowly and carefully, the bunch of
feathers , looking just like a camels-hair brush , will begin to
peep out of the orifice of the tube, and by and bye again spread
in full beauty. Even a slight shaking of the water will frighten
some of these worms into their shells, and in the smallest kinds
this sensitiveness goes so far that they feel even a momentary
darkening of the tank caused by the passing of a cloud.

- 21 -

i he sea we may often see such a natural garden, which,
looked at through the crystal-clear water of a rocky coast, is-
really an enchanting sight, and yields to the naturalist a rich
booty , not only of such worms, but of many other creatures
that there abide.

But not all Annelids secrete such calcareous shells or houses;
many kinds roll in the sand, and wet it with their slime, thus
forming soft sandy tubes. This is done by the Terebellae ,
whose yellowish-red feelers may often be seen sticking out of the
bottom of the tank, where they turn and twist about, seeking
food in all directions and looking like a knot of living threads.
Other worms cement together little stones, bits of broken shell
and such small things: and others again make shells of mud,
or dwell in long cartilaginous tubes, open at each end, which
look exactly like slender penholders; for example the Onuphis.
This last kind belongs to those Annelids which creep about with
their shells, like the well-known larva of the fresh-water dragon-
fly; while the first-mentioned adhere to rocks, pieces of wood
and other fixed objects, or stick the bottom of their tubes loosely
into the sand. ISJany kinds are a plague to navigation, for they
accumulate in such masses on the keel of a ship that its motion
is considerably retarded.

All these animals, when young, have an entirely different
form. On issuing from the egg they are larvae of a very pe-
culiar shape, and swim freely about. After a short time the}-
become fixed to some object and then by a complete metamor-
phosis , change into annelids and begin to secrete or make
their tubes.

These tube-inhabiting Annelids , of which a great man}-
beautifully coloured species are to be found in all soutbern
seas . correspond , as a second group , to a not less rich and
varied group of free Annelids. The Gulf of Naples has long
been celebrated among zoologists as the richest in the latter
animals; and already, including the tube-inhabiting worms,
more than 300 different species have been discribed. But only
a small portion are fit for the Aquarium, most kinds living in
the mud, rocky crevices and hollo,ws, and seldom being able
to bear the direct influence of the light for any length of time.
One of the most beautiful kinds is the Sea Mouse (Aphrodi-
te) , the prickly coat of which has at housand metallic col-
ours. Its nearest relation is Hermione, which in spite of its
beautiful name, is a very insignificant and disgusting creature,
the hooked spines of which easily fall out, stick in the hand

- 22 -

if one touches the animal and cause inflammation. This crea-
ture is one of the commonest in the Gulf.

Yery imposing are the Eunice, which attain o considerable
length. The undulating and lively motion of their glittering
bodies , which are set with hundreds of fringed gills , has a
beautiful effect. But they are very rare, and only to be found
in the Aquarium two or three times in a year. The yellow
Halla, of the same family, is found oftener. Besides the An-
nelids described , the visitor will find a variety of kindred
animals with similar habits; but to mention and describe them
all, would unnecessarily exceed the proposed limits of this
little book.

Lately the attention of naturalists has been particularly directed
to Annelids, because the study of comparative anatomy has di-
scovered points in their organism which seem to support the
hypothesis of a connection between these animals and the
Vertebrates. At present a lively scientific discussion upon this
question is going on , which is a great inducement to pursue
zoological inquiry in this direction.

Besides the remaining divisions of worms (not including the
innumerable intestinal worms of fishes and other marine animals
which, naturally, are not proper objects for exhibition in the
aquarium), many other smaller creatures live in the tanks, such
as the leaf-shaped, often gaily-coloured Planariae or whirlpool
ivorms', of the star worms (Gepliyrea)i\\Q?Q are the white Sipun-
Culus , Spurt-worm, which buries itself in the sand, and the
green Bonellia, which hides its round body in rocky holes, and
can extend its thread-like trunk to an enormous length. By a
canal in this trunk the animal conducts nourishment to its mouth,
which is situated at the root of the trunk. Until now this animal
has been a rare guest in the Aquarium, and has seldom shown
itself to the visitor for more than a few moments at a time.
It is oftener found in the Adriatic than in the Gulf of Naples,
but may be collected in any quantity on the coasts of .Dalmatia.
We must still notice a very peculiar group of animals, similar
to the worms, the Bryozoa, or moss-animals, so called from
the mossy-looking bunches they form. The position of this group
in the scientific system has always been very dubious, and even
now they are only classed provisionally with the worms. By ol-
der naturalists these animals were declared to be related to the-
polypes, and indeed the spectator might easily mistake the pretty
net-like frills of the Retepora, or the branching trees of the
Myriozoum and Eschara for corals. But closer examination

- 23 -

has proved that the small animals which form these branches
and frills are very differently, and much more highly, organized
than the coral polypes. They have a noose-shaped intestine, are
provided with a mouth, fringed with ciliated feelers, and have
a separate anus: muscles and nerves are also found. All these are
things which the polyps do not possess, and their entirely different
manner of development also teaches us that these two groups,
in spite of their outward" resemblance , are not in the least
connected. The Bryozoa are found in all seas, and reveal an
astonishing wealth of forms, the knowledge of which is opened
to us by an extensive literature relating to this group. Their
division into different kinds according to the delicate microscopic
details of their shells is the life's occupation of numbers of
zoologists, and lately it has been tried, by the study of their
development, to lift the veil that conceals their origin and re-
lation to other animal forms.

Crustacea or Crabs, Lobsters and Shrimps.

These animals form a very peculiar and strictly denned group.
Contrasted with the quiet dreamy lives of the zoophytes and
annelids, the monotonous motions of the apathetic fishes, or the
lazy rnolliisks and sea-urchins, the active and often comical mo-
vements of the different kinds of crabs are very attractive, and
we soon discover that the mental qualities of these creatures
far exceed those of most other marine animals. We are thinking
chiefly of the short tailed crabs and similar animals, which are
to be found in one of the smaller tanks; but, as the non-scien-
tific visitor is usually best acquainted with the lobster, we will
begin with the latter, and from it try to enable him to under-
stand the remaining forms of Crustacea.

The Lobster, (Homarus marinus) is, on the whole, an
enlarged copy of the fresh-water crayfish, and the visitor will
easily learn, from examining the large examples in the Aquarium,
what are the principal features of its organisation. The body is di-
vided into a segmented fore-part, covered by a single carapace or
upper shell; a head and breast piece and a hinder part composed of
jointed rings, forming the "tail" of the lobster, and ending in a
fin composed of broad flat plates. In the front pait of the head
and breast-piece are the eyes, two pair of antennae or feelers,
and a little farther behind and below, the mouth, consisting
of six pairs of jaws , the three front pairs being distinguished
as upper and under jaws , while the hinder ones are called

- 24 -

assistant or auxiliary jaws or jaw-feet. The action of this com-
plicated apparatus may very well be seen, when the lobster or
crab is eating. He grasps and turns his prey about with the
auxiliary jaws , while the fore-pairs are used for biting and
chewing. Behind the auxiliary jaws come five pairs of legs ,
the first three pairs of which end in claws ; the first pair ,
being of immense size and strength , serves also as a wea-
pon of attack and defence. Even under the tail there are se-
veral appendages like legs , which in the female , serve to
hold the eggs. If we wish to form a Schema of this physical
structure, we first take a series of rings or sections lying one
behind the other, of which each section carries a pair of lateral
members. These members are differently developed in harmony
with the principle of division of labour , and partly serve as
jaws and weapons, partly as egg- carriers, according to the seg-
ment to which they belong. A similar differentiation is shown
by the sections themselves, which are partly welded into one
piece , partly connected in a manner allowing of freedom of
motion. This different ution of originally similar parts gives the
measure of the animal's degree of organisation, and therefore
we consider the crab to be of a higher order than the Annelid,
for example, which is also divided into sections, but they are
not highly enough developed to serve for different purposes, at
least not in such a pronounced manner.

If we examine the lobster more closely, we see that he is
almost constantly fanning with his feathery jaws, and frequently
moves his legs and tail 'appendages in a similar manner. This
is his way of breathing, lust as lung-breathing land-animals
renew the air in their lungs by the rythmic expansion and con-
traction of the lobes of the latter, so the lobster, by the above-
named movements, pumps fresh water in to his gills, which are
situated at the base of the legs under the breast-plate.

An important period in the life of crabs and lobsters is when
they change their shells, when they may literally be said to creep
out of their skins. At such times a crack appears in the hinder
edge of the breast-plate, and the lobster slowly pushes its way
through this backwards , a troublesome and often dangerous
operation , for all the limbs , the thick claws , the eyes , the
feelers and mouth-apparatus , must be each drawn out of its
narrow case, and even the stomach is skinned ! Very often the
animal sacrifices one or both of its big claws , and its soft
body is in great danger until the new armour has become har-
dened , and then the animal instinctively iries to hide itself

- 25 -

until this has taken place. Freshly skinned and uninjured in-
dividuals look extremely gay in their new bright colours.

Of those habits of the lobster that can be watched in the
Aquarium , we specially notice its custom of digging ditches
and holes in the sand, partly for hiding-places, partly for burying
food, and also its manner towards its companions, with whom
it often engages in deadly combat, trying the gigantic strength
of its claws with only too much success. The invalids with ab-
breviated feelers and broken claws sometimes seen in other
tanks, are such unhappy creatures wounded in battle or during
the moult.

The native place of the lobster is mostly on the shores of
North-European seas, where it is largely taken. Lobsters are
caught in baskets trimmed with bait ; into these they creep at
night. Lobsters are rare in the Mediterranean, and they com-
mand a higher price in the southern markets.

In the adjoining tank visitors will find a near relation of
the lobster : the crawfish (Palinurus vulgaris) , sometimes
called the prickly lobster and often mistaken for the true lob-
ster. But a mere glance shows the difference between them.
Its want of claws, its spiny shell, and immense feelers strike even
an unpractised eye , and closer comparison reveals numerous
other differences, which we leave our reader to find out for him-
self. The habits of the two animals are, however, very similar,
but the crawfish is more companionable, not so warlike and mo-
re lively ; it likes to climb the rocky sides of the tank, which
it does with great agility, and feeds on shell fish, which it cle-
verly opens with the strong claws of its fore'legs In the Me-
diterranean it is far more frequent than the lobster, and is found
on all the rocky shores of the Gulf of Naples. It endures con-
finement very well.

One of its relations is the great Flat-Lobster (Scyllarus la-
tus), a very lazy and clumsy fellow, who passes the greatest
part of its life in sitting still in a crevice of the rocks. Its
thick body is generally covered with mud and biown Algae
(Diatoms) so that it is often mistaken for a stone. It uses its
front feelers, which are shaped like two broad shovels, as weapons
of defence. The hinder and normally shaped feelers are violet-
coloured , and with these the animal constantly feels about.
When feeding, it hides its food with its shovels.

There will often be found in the tank containing crabs, the
little Flat-Lobster (Seyllarns arctus), which is of a more li-
vely and decided colour, climbing in troops on the sides of the
tank. The Lioncrabs Galatea, Munida are also near relations.

- 26 -

Of the small long-tailed Crustacea that often live in the Aqua-
rium we will mention the delicate , often transparent praicns
and slirimps, such as the Palaemon, Crangon, Alpheus,
Peneus , Lysmata , and others , which are remarkable
for their merry way of jumping. The first named inhabits all
rocky coasts in troops, and is food for innumerable other crea-
tures , being chiefly used in this way in the Aquarium. The-
motion of these prawns in walking or swimming is very light
and graceful , and their sensitiveness so great, that they feel
the slightest shaking of the water, and respond to it by immense
leaps. They are also sensitive to sound, as is proved by expe-
riment ; their organ of hearing is situated at the base of the
hinder feelers, and consists in a little bag lined with fine au-
ditory hairs , and opening outwardly in a slit. The waves of
sound cause these fine hairs to vibrate, and the motion is com-
municated to the auditory nerve. But to strengthen the sound
the ear-sack contains so called auditory stones , concretions
which are often lost , and then the animal replaces them by
little grains of sand, which it sticks into its ears!

A rare creature among shrimps is the Stenopus spinosus,
an extremely delicate and pleasing animal, which may now and
then be found in a separate tank in the Aquarium.

We will now turn to a curiously developed crustacean, which
may be called an intermediate member between the long-tailed
Crustacea just described and the Brachyura or short-tailed
crabs. It is the Hermit-crab (Eupagurus).

A whelk-shell running on the legs of a crab, and carrying
sea-anemones on its back — such is the first impression made on
any person looking at a hermit-crab for the first time.

The droll figure , which seems composed of parts of three
different animals , at once interests us and excites a wish to
learn more about it. The matter is simpler than it seems, and
is explained as follows. Hermit-crabs are animals who take up
their quarters in the empty shells of Mollusks, gathered at the
bottom of the sea, and chosen according to the size, that is,
the age, of the crabs which intend to inhabit them. When the
crab has chosen his house, he inserts himself into it backwards,
and fastens himself firmly by the hind part of his body. This
hind part has become , in the course of many thousands of
centuries of adaptation to this mode of life, altogether unsym-
metrical and soft, and resembles a long bag furnished with
a pair of little hooks at the end for sticking fast in the
shell , and by this means the animal adheres so firmly to-

- 27 -

its dwelling that it is torn if we attempt to drag it out.
The shell protects the soft body of the crab, and is generally
so big , that the crab can completely conceal itself when in
danger. As the animal grows, it must naturally remove to a
larger shell , which operation is effected with great skill and
caution. Having found a shell to suit him, the crab first ca-
refully examines it all over, poking his claws into it to make
sure that there is nothing suspicious at the bottomland, if all
is right, he at last carefully prepares to effect the removal. He
gets hold of the shell with his claws , places it upright with
the opening turned towards him , and then , with one quick
movement, forsakes his old shell and slips into the new one,
as if he very well guessed what a tit-bit his soft and juicy body
would be for a hungry fish.

Bnt what business have the sea-anemones that are regularly
settled upon all the shells occupied by hermit-crabs, often from
three to six in number , and yet nowhere in any bodily con-
nection with the crab? The fact is, that the hermit-crab and
the sea-anemones have formed an alliance. The latter protects
the crab from its enemies by means of the poisonous nettle-
cells of its tentacles, while the vagabond habits of the crab
give the anemone a greater chance of finding nourishment, for
the latter is being constantly brought into contact with all kinds
of animal life, or else catches the bits that fall during the crabs
own meal. This fact is proved by the beautiful purple -spotted
Anemone Adamsia palliata, which always fastens on the shells
inhabited by the Eupagurus Prideauxii and is usually so pla-
ced that the orifice of its mouth is turned downwards. But the
most wonderful thing is that the crab knows its friends, and
not only tries to put anemones on a shell that is without them,
but actually, when it changes its abode, takes its companions
along with it !

An experiment , in which all the sea anemones were 'taken
away from the shell of a hermit-crab, and replaced before the
eyes of the experimenter by the crab pressing them with his
claws out the shell until they had again fastened , places the
above fact beyond all doubt, and proves the alliance to be one
of the most remarkable known among the lower animals.

The life of the hermit-crabs in the Aquarium offers a picture
rich in varied and amusing scenes. The droll fights of the little
troop, the impudent seizures on the one part and the resolute
defence on the other during the common meal , involuntarily
excite the laughter of the spectator who is often greatly surprised

- 28 -

by various traits of artful and calculating utilization of the si-
tuation on the part of these little creatures. Hermit-crabs come
next in rank to the short- tailed crabs, to which we now turn
our attention.

In the hermit-crabs we found a retrograde development of
the hinder part of the body in consequence of the long conti-
nued habit of living in shells. In the short- tailed crabs this
retrograde formation has gone much further, but in favour of
another principle, that is, of fredom of movement. Here we see
the larger portion of the body, which in the lobster we called
the tail, reduced to a small round or three-cornered plate, which
is doubled under, the edge lying close to where the legs begin.
In the female this plate is hollowed like a dish for the reception
of the eggs; in the male it is simply a pointed three-cornered
plate stuck fast into the niche destined for its reception. But
the forepart of the body is developed crosswise and is generally
of an oblong or square shape. The wellknown purse- crab may
serve as a type of this group ; it is familiar to most people
from collections, engravings or personal observations.

We will next draw attention to the crabs with a three-cor-
nered head-and-breast plate, of which the species Pisa, Lissa,
Maja, Inachus, and Stenorhynchus are the most interesting.
What will most strike the observer in these animals is their
being covered by all kinds of foreign substances. One carries
on its back and legs a complete forest of algae and moss-ani-
mals; another glories in a strange decoration composed of the
stems of Hydroid polyps, which . grouped in a bunch , adorn
the spikes of his forehead ; others, for example the Inachus
drag about , clinging to their long thin legs , plants , spon-
ges and ascidiae ; — in short , the more crabs we examine
the greater variety of toilettes shall we see: and their use ?
They are the best possible means of concealing the animal
from its enemies and from its prey. All these things have not
voluntarily fastened themselves to the crab , but have been
artistically placed there by itself, with — wehardly dare say -
conscious intention, but certainly with an hereditary instinct
that impels the animal thus to disguise itself; and the mask,
in many cases, is so successful, that it even deceives the knowing
eyes of men. All these three-cornered crabs are extremely
sedentary, and, as they remain motionless when alarmed, exact-
ly resemble stones overgrown with moss or sea-weed. Their
apparatus for fastening these foreign bodies in their backs
consists in a number of hooked bristles, arranged according

- 29 -

to a certain law all over the> body, and between which the
crab with its claws very cleverly hooks fast the algae and
other things. The large Maja Squinado, sea- spider, or more
correctly , spider-crab , for there are no spiders in the sea ,
covers its back with little stones and shells, instead of with
such a miniature wood. Among the crabs with four-cornered
bodies we meet with similar habits. The Dorippe lanata
gets hold of any living or dead body within its reach , holds
above its body with its hinder reversed legs, and thus shielded,
stalks proudly about. Whatever it may find, — sea cucumbers,
ascidiae, crabs , star-fish, fish heads, bits of glass or wood —
iu short anything and everything which can serve as a shield,
is annexed without further ado, and naturally, in case of the
desired shield being a living animal, there ensues a comic con-
flict between the instict-obeying crab and its reluctant victim.
Another animal the Dromia, or wool-crab , covers its back with
a certain kind of sponge— the orange- coloured Suberites — so
completely, that when looked at from above nothing is to be
seen of the crab but its legs. These crabs are also provided
with a pair of legs turned backward for this purpose , which
hold the sponge fast. The Homola and Ethusa have similar
habits. The simplest mode of escaping danger is by burying in
the sand, a habit seen in the Calappa, or bashful crab. With
a few vigorous movements of its large shovel- shaped claws ,
this animal buries itself up to the eyes and carefully examines
the neighbourhood from its retreat.

Tho same habit is seen in the active shore-crabs , such as
the Carcinus, Paehygrapsus, Eriphia, and the Portunus
and Lupa, whose slyness and activity are really astonishing,
and, with their ability to move on the land, indicates a higher
organisation. Whoever has tried to catch these crabs in their
natural haunts will remember the difficulty he had to secure
even one, and also the cleverness with which the little fugitive
availed itself of every cranny, and the bold manner in which
it defended itself when driven into a corner. The strong Eri-
phiae are especially ready to fight and pinch with their pow-
erful claws everything held out to them. In the Aquarium
we have seen them break thick glass tubes in this manner.
All shore crabs can live for a long time out of water, and move
on land with almost the same agility as in the water.

Besides the above described crabs with five pair of legs, we
must notice one belonging to a lower order. This is the grass-
hopper-crab, or Squilla mantis, a slender, active and pre-

- 30 -

datory animal, which in many respects reminds one of the Mantis
religiosa, or praying mantis, a land grasshopper. Its legs espe-
cially — which are provided with pointed claws that snap
like the blades of a penknife, and can be darted at the victim
with great velocity and strength — resemble those of the Mantis.
The Squilla is a very clean animal, and almost constantly oc-
cupied in carefully cleaning all parts of its body. It may be
seen making its toilette in all sorts of attitudes. Now the eyes
and feelers , now the mouth and its parts , now the legs and
segments of the body are brushed and stroked till no foreign
particle is left adhering to them. The object of this scrupulous
cleanliness noticeable in many crabs and insects (for instance,
the common housefly) is scarcely aesthetic, — we rather suppose
it to be a very practical one — the preservation of the different
delicate sense-organs.

The great army of crabs of the lower order — of the variety
of whose shapes the naturalist alone has till now the slightest
notion — is far less adapted for exhibition in an Aquarium than
the higher Crustacea. This is partly owing to the small size
of most kinds , which is often combined with complete trans-
parency , so that they can only be seen with a glass ; and
partly to many being parasitic and hidden in the intestines of
other animals. We must therefore confine ourselves to mention-
ing the most striking of those now and then to be found in
the Aquarium, aiding our discriptions by explanatory remarks.

The visitor will often find, sticking to some fishes, especially
to the wrasse, the parasitical species Anilocra and Cymothoa,
belonging to the sub order of the Isopoda, for which the well-
known wood-louse — a crab converted to a life on land — may
serve as a type. They fasten themselves into the head , the
eyes, or the tail-fins of a fish, boring into it with their mouths
and the sickle-shaped claws of their seven pairs of legs; or they
are found in the gills and throat of their victim. The Anilocra
attains a length of about an inch and a half. These animals
hook themselves so firmly to their victims that no effort of the
tortured animal can shake them off. The female parasite carries
her brood in a particular place on her belly until the young
are ready to creep out.

Most species of the group Hay -crabs or Amphipoda - of
which the reader is perhaps acquainted with the Gammarus
pulex or common flea-crab that lives by thousands under the
pebbles of running brooks — live in the sea. The north and
arctic seas especially are so full of these active little animals

- 31 -

that the carcases of whales or other large sea-creatures are
soon reduced to skeletons by their aid. Particularly interesting
are the Hyperine , to which belongs the Phronima, a little
pelagic crab of crystal transparency that , strangly enough ,
lives in and on the bodies of young Pyrosonia which it eats
until they are reduced to mere empty little barrels, and then
uses them as moveable habitations. The Phronima fastens itself
by its forelegs within this empty barrel, sticks out the hinder
part of its body, and using its tail-appendages as oars, swims
about, carrying its jelly -barrel with it. This small Diogenes
also uses its barrel as a nursery; for not only does it fasten
its eggs to the inner walls, but the young ones remain in it
for a considerable time even after they have crept out of the
eggs. This creature is caught in the surface of the sea in sur-
face-nets , together with jelly-fish, Siphonophores, and other
representatives of the pelagic jelly animals ; especially in win-
ter and spring.

The Cirripedia are considered to be the lowest order of
the Crustacea, and are so unlike the typical form , that it is
only quite lately that naturalists have clearly recognized their
nature. Even Cuvier thought the hard-shelled Balanus and
Lepas were mollusks, until subsequent examination — obser-
vations on the structure of the young ones and the mi-
nute anatomy of the adult — proved them to belong to the
Crustaceans. How much more difficult must it be for a non-
scientific spectator to accustom himself to the idea that these
creatures, so unlike in appearance, are indubitable relations
of the well known crabs. It may be of assistance to know that
their mollusk-like form is the result of a very extensive retro-
grade metamorphosis. When young, all these creatures are very
lively, freely jumping about in the water. The}?- have a pear-
shaped body and three pairs of feet that serve as oars. This
form is zoologically called the nawp/tus-form (just as the com-
mon larvae of the larger crabs are called zoed). But after several
ecdyses they fix themselves by the heads, the skins secrete a
covering composed of calcareous plates, which completely hides
the crab and permits the feet only to protrude through a gap.
The movement of these segmented feet may be beautifully seen
in the Balanus as well as in the Lepas. For these animals are
continually moving them in order to conduct a current of fresh
water to their gills and mouths. On the edge of the rocky coasts
of all seas the Balani form a characteristic border , and cling
so fast to the stones that the heaviest breakers cannot destroy

- 32 -

them. They bear equally well being left dry during ebb-tide,
the small quantity of water they retain within their hermeti-
cally closed valves enabling them to resist the greatest heat of
the sun. Many kinds are found settled on whales in heaps.

The Lepas settle by preference on floatings bodies, ships ,
pieces of wood , and similar things being covered by them.
Their name is derived from the fable that out of them is de-
veloped the barnacle-goose (1).

The Scalpellum vulgare also belongs to the Lepadidae. It
is a deep-sea animal remarkable for its sexual condition. These
animals are hermaphrodite, but as if to secure the preservation
of the species, they carry, in a special bag or pocket, several
dwarf or complementary males of infinitesimal size !

The most remarkable thing in retrograde metamorphosis is af-
forded by the parasites known as root-crabs , which live on the
hind parts of prawns and hermit-crabs. They are nothing but un-
shapely sacks filled with eggs and connected with the bodies of
their victims by a short stem and a bunch of branching sucking
tubes, through which the animal juices are drawn. The nature
of such forms which parasitism has caused to degenerate until
they have lost all resemblance to crabs, could only be deter-
mined by naturalists by the study of their development ; and
indeed the problem was only solved when the nauplius-larvae
were discovered.

Ilollusca.

The highest developed class of Mollusks is that of the Ce-
phalopods , distinguished by a head separated from the body,
and a mouth- orifice surrounded by prehensile arms. The Aqua-
rium contains the following kinds:

The Eight- armed sea-poulp or octopus (Octopus vulgaris),
frequently found on the rocky coasts of the Mediterranean. This
creature has a body like a bag, which we see breathing with
a rythmic motion; this is the body proper of the animal and
contains the intestines. The small head at the top contains the
two large eyes, and from it proceed eight arms covered on
the under-side with sucking-disks. The mouth lies in the cen-

(1) This myth, which can be traced back to the 12th century, probably owed
its orio-m to the monks of that period , who wished to add something to
the scanty fare allowed during last. At least according to credible wit-
nesses , it was affirmed by Irish and French bishops that barnacle-geese
xvere produce of the sea, and therefore no flesh.

- 33 -

tre, hidden by the intermediate skin that connects the arms
at their base. This mouth is armed with hard mandibles, some-
thing like the bill of a parrot. When the animal breathes, we
see at one side of its body a slit or fold in the skin which
alternately opens and shuts and from which, when it is open,
protrudes a short thick tube or siphon, the movements of which
alternate with that of the slit. This latter opens into the cavity
that contains the gills, and through it the water enters. The slit
is shut during expiration, the exhausted water being expelled
through the tube or siphon. This organ also acts as a swimming
apparatus, for the impulse of the expiration drives the animal at
will backwards through the water, while the arms, rapidly exten-
ded or contracted, increase the strength of the stroke. With
its arms the octopus can also creep and climb as well as seize
and hold its prey. The arms are provided with a double row
of sucking-disks, which act as an adhesive apparatus. The food
of the octopus consists chiefly in crabs and fishes. The octopus
is a powerful robber, lying in ambush for its prey among the
rocks. In the Aquarium these creatures drag large stones into a
heap and hide behind them, and, in such a case, their power of
changing colour and imitating that of their surroundings is of
great use. They grow to a considerable size, and gigantic exam-
ples observed in the ocean are the historic germ of the legend
of the Kraken. Pliny relates a story of an animal of this kind
which came at night to the fish-tanks of Carteja, and frightened
the dogs away by its snorting and its terrible arms. Its head,
which was shown to Lucullus, was as large as a barrel holding
fifteen amphorae of wine; its arms were so thick that a man
could scarcely clasp them, and thirty feet long ; each sucking-
disk contained a jar of water, Montford told of an octopus that
tore a couple of sailors from the rigging of a ship near St.
Helena; the end of one of its arms, which caught among the
tackle and was hewn off, measured 25 feet. Later reports of a
gigantic octopus have been brought by the French ahip Alecto,
which met with one on the 30 November 1861 between Tene-
riffa and Madeira. The animal measured from 15 to 20 feet,
not reckoning its immense arms. Its colour was brick-red; its
eyes enormous, with a frightful rigid stare. Its weight was
reckoned at 2000 kilogrammes. After pursuing it for three
hours the crew only succeeded in cutting off part of its body.
The octopus is caught on all Mediterranean coasts; it is en-
ticed by bait, at which it rushes, and is then drawn up by a

- 34 -

string. It is frequently found in the fish-market, for the arms
of the younger animals are eaten and highly prized.

A near relation of the Octopus is the Eledone moschata,
the musJc-eledone, smaller than the animal just described, and
furnished with only one row of sucking-disks in each arm. They
are shy creatures, fond of hiding in corners; when taken out
of the water a delicate odour of musk is perceived. They are
very numerous and common in the market, but generally eaten
only by the lower classes.

One of the most interesting and important cephalopods is the
Sepia (Sepia officinalis), or cuttlefish, more correctly, cuttle-
snail. Its body is oval and flat , sorrounded with a hem of
fin. Beneath the skin of the back is found the bone known as
os sepiae. Its arms are much shorter than those of the octopus,
and are usually folded together in a point. Hidden amongst
them is a longer pair of prehensile arms which are darted for-
ward when the animal catches its prey.

What is most interesting in the Sepia are its powers of
excreting an inky fluid and changing colour. The former is
common to all the species, but the sepia makes a more fre-
quent and abundant use of it. This colouring matter, used by
artists, is the product of a gland, the so-called ink-bag, the
contents of which can be emptied out of the siphon. A small
quantity of this fluid expelled with the water is sufficient to
enfold the animal in a black cloud , frightening its pursuers
and covering the animals' s retreat. This colouring matter is
dried and sold in the market, and can even be obtained from
fossil animals in a useful state.

The wonderful play of colour in the living animal proceeds
from the cells of the skin, which are filled with an extremely
thin colouring matter; muscular fibres, that stretch these cells
and alter their size and shape , occasion an almost constant
change of tint and the appearance and disappearance of stripes,
spots and clouds of colour, that are visible or not, according as
the animal is excited or at rest. Besides this, we notice a pe-
culiar glittering and iridescence of the skin, occasioned by the
breaking of the rays of light through the tiny plates or spangles
lyingh thick below the colour-cells. The sepias are perfect ma-
sters of this play of colour, as is proved by their adopting the
tint of the sand or rocks on which they lie. The sepias are
of different sex. When the male courts the female its excite-
ment causes its skin to assume the most brilliant colours. There
may then be seen vivid zebra like stripes, while the eyes have

- 35 -

a metallic bluish glitter. After pairing, the female lays its large,
black, pear-shaped egg-capsules singly upon the branches of
coral or algae, usually close together, the whole looking like
a bunch of grapes. When the young leave the eggs, they are
exactly like their parents, and at once begin to change colour
and spurt ink. The sepia is in great request in the market;
the meat is eaten and the bone or shell used for polishing
wood and making toothpowder.

Among the inhabitants of the Aquarium may be seen, particu-
larly in winter, the Calmar or Squid (Loligo vulgaris). These
semitransparent creatures, shaped like winged arrows, are un-
fortunately far too sensitive for confinement. Beating their
delicate wings like a flock of birds, they continually swim
backwards and forwards without turning until they die, which
is generally a few days after they are caught. They are never
seen at rest, and the slightest disturbance throws them into
violent agitation, when they dart about like arrows, and their
milk-white bodies seem to blush rosy-red. They are fed with
small shrimps, and, when feeding, use their prehensile arms
like the sepias. They are greatly liked as food. Their bone or
shell is transparent as glass, very flexible, and shaped like a
feather. They excrete the inky fluid in great quantities, whence
their Italian name of calamajo (ink-pot).

The Snails, like the cephalopods, have generally a clearly
distinct head , and a memberless body provided with a flat
base for creeping , the so-called foot. In many species , the
greater part of the abdomen is enclosed in a spiral calcareous
shell or house , into which the rest of the body also can be
withdrawn. This shell is excreted by the so-called mantle , a
fold of the skin, and is connected with the animal only by a
muscle. Scientific conchological selections bear witness to the
beauty of these shells- in form and colour. Most kinds belong
to marine snails. The chief of those from the Gulf of Naples
which are in the Aquarium, are the following:

The Worm-snail(Vermetus); remarkable for the irregularity
of its shell, which is fixed to one place. At first sight it exactly
resembles the twisted calcareous tubes of the Serpulae, a group
of hairy marine- worms;— but on looking closer, you recognize
the stopper-shaped head of the snail, with its short feelers ,
and see that it is very different from the brightly- coloured
feathery head-gills of the Serpulae. These animals feed on
the little cray-fish and worms that play near them in the water.
AVhen they are disturbed, they at once retreat to the bottom

- 36 -

of their shells. They stick their eggs to the inner sides of their
house; when the larvae issue from the eggs, they swim about,
until, after a while, they also settle in one place.

The Murex or purple-snails are represented by many kinds
(M. trunculus, brandaris), which belong to the commonest shells
of the Mediterranean , and in ancient times played an impor-
tant part. For from these mollusks was obtained the real pur-
ple used by the ancients to dye their royal garments. This pur-
ple substance is excreted from a gland lying in the animal' s
mantle, and, when freshly taken, is white or slightly yellow.
Placed in the sun it changes to lemon-colour and green, and
then to a beautiful violet, which becomes darker and darker the
longer it is exposed. The shade depends on the quantity of mat-
ter used, so that the dyer can obtain any tint he desires. The
making of this purple dye was a large branch of industry among
the ancients, and factories for the purpose were scattered all
over Italy and Greece. Monte Testaccio in Rome is formed of
the refuse from the greatest of these factories. Also in Aquileja
traces have been found of a purple-dye factory. In our days the
industry has entirely vanished, though the colouring matter ,
so susceptible to light, is very well adapted, as experiments
have proved, for photographs on silk and other fine stuff.

The Tritons-horn (Tritonium nodiferum) is a large plump
snail, with protruding head , feelers provided with eyes, and
a long elastic proboscis. This snail creeps slowly about at the
bottom of rather deep water and lives on animal food. Its
heavy, beautifully-twisted shell was used in ancient times as
a war-trumpet, and even now is employed as a signal-horn by
workmen (for example, the master-masons in Naples use it to
call their people together). For this purpose the point is cut
off and you-blow through the hole. The peculiar rushing sound
heard in holding a large shell to one's ear is produced by the
resonance of its hollow convoluted interior, which rejects the
waves of sound. In an absolutely quiet place the shell would
not sound at all.

The barrel-snail (Dolium galea) is the largest in the Me-
diterranean, with a thin shell, shaped like a barrel, a white-
body spotted with dark brown, and a large proboscis. A pe-
culiarity of this animal is the shape of the salivary glands ,
which attain considerable size (1 £ inches in diameter) , and
exude a fluid containing more than 2 £ per cent of free sulphuric
acid and nearly f of free muriatic acid. When defending itself,
the animal spurts out of its mouth a considerable quantity of

- 37 -

this fluid. Until this day it is a^riddle how such corrosive mi-
neral acids can be freely produced and retained in the body
of these snails.

Akin to the above animal is the Helmeted-snail or Cassis
of which one kind (C. sulcosa) is often found in the Aquarium.
In habits and frequency they resemble the Barrel-snails, and
are much prized for the beauty and elegance of their shells.
It is from the shells of many kinds of this snail that are cut
the well-known shell-cameos. For this purpose suitable pieces
are sawn out. and the exterior polished, while the interior is
left untouched. The relief is then worked out, use being made
of the different-coloured layers.

To these shell-carrying snails is related a group of mollusks,
distinguished as rnollusks with hind gills, because, contrary to
those we have just described, their gill lies behinvd the heart.
They either have no shell at all, or it exists in a rudimentary
form, hidden in the mantle, similar to that of the naked com-
.mon snail (Limax). To this group belongs

The Sea-hare (Aplysia leporina), a dark brown , rather
large snail , with two pair of feelers, the hinder ones , which
stand erect , actually resembling the ears of a hare , whence
the name , sea-hare. The mantle is extended into two large
wing-like flaps, by means of which the animal swims. Usually
creeping lazily among the rocks, when it wants to swim it fans
the above mentioned flaps until the movement raises it from
the ground. Once afloat, it swims well and quickly, but only
for a short time. When teazed, it expels not only the water
contained in its body, but also a beautiful violet-coloured fluid,
which, like the ink of the Sepia, serves as a weapon of de-
fence. Chemical examination proves that this colouring matter
has the properties of a concentrated aniline solution, and re-
acts in the same manner as an artifical aniline dye. The poi-
sonous character of the fluid seems to have been known to the
ancients, for Latin authors mention its being used for charms
und poisonous draughts, after taking which the victim suffered
torture until the sea-hare dies. Large snails yield about two
grammes of pure dry colour.

The Aplysiae are vegetable feeders, and graze on the weed
at the bottom of the sea in troops. It is a pretty sight when
several stones overgrown with algae are brought to these snails
in the Aquarium. They come creeping from all sides to feed,
^and in a few hours the stones are denuded of a1! the vegetable
matter. The Aplysiae endure confinement capitally on this food,

- 38 -

grow and thrive, and often lay their eggs in the form of long,,
yellow-and- violet twisted strings , which hang from the sides
of the tanks.

One of the most beautiful among these hind-gill snails( Op istJw-
Iranchia) is the large Tethys leporina. It has a delicate ,.
white, half-transparent body, a head distinguished by a large-
umbrella-shaped sail, and its back is adorned with two kinds
of appendages in a double row : that is , small bunch-shaped
transparent gills, and larger, hollow, pear-shaped fringes crossed
by bright red-and-black lines; the function of these fringes is
still unknown. They easily fall off, especially shortly before
the animal dies.

This snail belongs to the periodic inhabitants of the Aqua-
rium, like the pelagic animals. It is caught by the fishermen
in glasses when floating on the surface of the sea, and when
f^esh and lively, is a beautiful object, so transparently white,,
with its coloured fringes and graceful motions in swimming. It
swims by alternate pulsations of its sail and quick undulations
of its body. In confinement it rarely lives more than a few
weeks.

Among the larger specimens of the hind-gills, we must men-
tion the Pleurobranchus, which has a shield-shaped mantle
and lateral protruding gills. Also several species of the Doris,
with a feather-like tuft of gills on the hinder part of the back.
From these snails come the yellow and white tangled jelly-
like strings, containing thousands of eggs, that are seen glued
to the rocks of the tanks.

The Mollusks also furnish a contingent to the pelagic world;
of crystalline* animals. Besides the transparent Medusae we find
the wonderful Heteropods or Keel-snails , and the Fin-snails
(Pteropods). Especially in spring and autumn, when the sea is
crowded with pelagic animals of all kinds, then these small and
lively creatures make their appearance either periodically or
at incalculable periods. But they cannot endure confinement
long, sometimes living only a few hours, and on this account
they are rarely to be found in the tanks. —Among the keel-
snails the genus Pterotraehea deserves special notice. These-
animals are long and transparent as crystal, with proboscises
bent like a knee , axe-shaped oar-fins ( which answer to
the foot of a snail) , and a knot of intestines glittering like
silver. These creatures swim actively by rapid lateral mo-

- 39 -

tions of their flexible bodies, and rapaciously catch with their
elastic hooked tongues all the small pelagic animals that sur-
round them.

The fin-snails have a curious shape, which differs in almost
all respects from that of the typical snail. The head-part is
only indicated by a mouth surrounded by rudimentary feelers.
The body, which is of various shapes, is frequently hidden
by a delicate shell; but the most singular organ is a pair of
large wing-like fins , which are situated on the head or neck,
and are used by the animal like the wings of a butterfly. The
people call this creature far folia di mare (sea-butterfly). The
most frequent kind is the Hyalaea, with a palebrown horny
covering , and large ever-moving fins. It often appears in
swarms, but in the Aquarium lives scarcely a day.

The Cymbulia and Tiedemannia are much rarer.

The Shellfish are the lowest group of mollusks. They are
externally distinguished from the snails by their shell, which
invariably consists of two moveable valves, that close by means
of a muscle, and open, when the muscle is relaxed, by means
of an elastic band on the so-called lock. The want of a head
is an important characteristic of these animals. The organ of
locomotion is a foot generally shaped like a wedge or tongue,
and capable of being pushed forward by swelling. The body
is covered by the leafy gills and mantle-plates, which secrete
the shell. These mantle-and gill-plates lie under the shell like
the leaves of a book. The internal organs are : an intestine ,
a liver, a heart, kidneys and the organs of generation. The
ciliated membranes of the gills and the mantle conduct the
water containing air and nourishment. A nervous system and
organs of sense (ear-bladders and often eyes) are found in all
these animals. — The greatest number of shell-fish beiong to
the sea, where they either stick immoveably to some object,
like oysters, or hide in the mud, and are capable only of ex-
tremely slow movements ; very few canswim or jump. From
the large number of those living in the Mediterranean we will
choose the most interesting and important.

The common mussel (Mytilus edulis) has a blueblack three-
cornered shell with a pointed whorl. This animal possesses a
so-called byssus-gland, from which it spins horny threads or bys-
sus wherewith it fastens itself so firmly to rocks or piles that
the most violent breakers or currents of water are unable to

- 40 -

tear it loose. When it wishes to change its place , it spins new
byssus-threads , and tears the old ones. By repeating this ope-
ration it slowly moves forward. The mussel thrives best in
north European seas, where it is in fact the object of exten-
sive culture. So-called mussel-logs are sunk into the sea for
the mussels to settle upon, and are then drawn up from time
to time covered thickly with the animals in all stages of de-
velopment. In the market at Kiel about 800 tons of mussel are
sold annually, each ton containing on an average 4200 animals,
so that altogether 3,360,000 mussels are taken in one winter.

Very interesting in its habits is the Stone-mussel (Litho-
domus lithophagus). It is always found in holes made by
itself in the rocks or in corals. The smooth oval shell is
brown and shining, the animal a favourite food, and therefore
often in the market. How these creatures bore into the rocks
is still undetermined. Their shells being perfectly smooth, they
cannot make holes by. filing, as is the case with the Phola*
or boring-mussel. It is probable that the effect is produced by
the dissolving power of some animal secretion. Internally the
holes made by the Lithodomus are perfectly smooth and regu-
lar. These mussels have become celebrated through the Temple
of Sempis at Pozzuoli, on the columns of which is seen a sharply
limited belt, six feet wide, of holes made by the Lithodomus.
The temple at some period sank below the level of the sea
with a subsidence of the land , and was raised again subse-
quently.

The Pinna are large thin-shelled club shaped mollusks, which
stick the pointed ends of their shells into the soft bottom of
the sea. They also possess a byssus gland, which , however ,
is much larger and finer than that of the common mussel, and
the threads produced were once manufactured into all kinds of
fabrics. As late as last century factories might be found in
Taranto, Naples and Sicily, occupied solely in manufacturing
a sort of silk from mussel-threads: « the shining green bundle
of threads was washed twice in soap and water and thrice in
pure water , then immediately hatchelled , and spun on the
distaff into a yarn of three threads, from which gloves , sto-
ckings and even whole dresses were made. »

Now and then pearls are found in the Pinna, but they are
of no value. The ancient fable of the mussel-guard (Pinnotheres),
which warned its host of approaching danger, and received a
lodging in recompense, was founded on the fact that in almost
all mussels is found a small crab, such as is also seen in the

- 41 -

ascidians, sponges and other low forms of creation; but it is
of no sort of use to the Pinna.

If the creatures here described seem to be the embodiments
of the principle of stability, the cockle and scallop, on the
contrary, prove that not all the members of this family share
in difficulty of locomotion.

The cockles or Cardium. are a genus with very numerous
and diversified species, and take their name from the shape of
their shell which is remarkable for its protruding spiral whorl,
and radiating ribs, often set with spines. The animal has a
long, rounded, bright red foot, of which it makes a very pe-
culiar use. Fixing it firmly on the ground, it stiffens it by
swelling, and then bounds forward for several feet. This jumping
is a very unexpected feat for a shellfish. The animal can also
sink deeply into the sand with surprising velocity by rapidly
extending and contracting its foot , the point of which being
hooked serves as an anchor. Cockles are much prized in the mar-
ket, and are caught in immense quantities on the English coast.

The Scallop (Pecten), the largest species of which is the
Pecten jacobaeus, or pilgrim's scallop, has been used from
old time to decorate the hats or cowls of pilgrims, and belongs
to the best-known members of the whole group. It has one
round and one flat valve with radiating ribs. On the thicker
edge of the mantle are numerous short feelers and eyes, which
can be seen when the valves are open, the eyes glittering like
gems. They probably serve to guard the edges of the shell.
This animal makes movements as surprising as the jumping
of the cockle. It darts about in the water with arrowlike swift-
ness by opening and shutting its valves in quick succession ; as
soon as the movements cease, the animal falls to the ground.

The most important and best known of all shellfish is the
oyster, Ostrea edulis. Its irregular, fiat, leafy and ugly shell,
which is generally fastened by its thick side to some stone or
piece of wood, is known to everyone. The animal itself effects
the adhesion by means of a secretion that penetrates through
the shell, and as the animal grows, the surface of adhesion is
enlarged. The oyster is remarkable for the retrograde formation
of its foot after it has fixed itself, and for being hermaphrodite,
which is the case with very few shell fish. The same individual
generates both the sperma and eggs. The number of the latter
is enormous, and is calculated by many naturalists at several
millions. The young oysters remain in the shelter of their pa-
rents' mantle until their shells are far enough developed for

- 42 -

them to fix themselves to some object. Spawning-time is in
summer.

The geographical diffusion of the oyster is from 60° north
latitude to the tropics and the southern hemisphere. On
European coasts the oyster is the object of extensive fishery,
and it is largely cultivated in special oyster parks, for it is
not only an article of luxury, but even, especially in England
and America, a national food. The ancients also cultivated oysters
artificially. A century before Christ, according to Pliny, one
Sergius Grata was the first to make an oyster-park on a large
scale. The Romans of the Imperial age, on whose tables the
oyster was never missing, considered those the best that came
from Lake Lucrine, near Bajae. At Brindisi oysters were also
largely cultivated as at Taranto now. In the middle-ages they
were cultivated in England and Denmark. Now the principal
oyster-parks are on the Atlantic coast (Arcachon, Ostend), and
in the Adriatic. They are large stone-beds connected with the
sea by sluices, and frequently cleansed. The oysters are sowed
in these places and carefully tended till sufficiently fattened
for the market. Natural oyster-banks, for instance in the shallow
water of the coast of Holstein, yield a large supply.

Tin* Sea-Squirts (Tuaiicata).

We stand before a tank containing a curious picture of still-
life. Groups of white , half-transparent double-tubes , among
which are scattered some rough lumps that look as if made of
white glass or of wrinkled brown leather, are seen together with
splendid red things shaped like a sack with funnel-like openings
at the side and upper end. In one place lie lumps like greenish
jelly, and the sides of the tank are covered with a varicoloured
crust of starry pattern — all strange forms of which the inhabitant
of the inland is entirely ignorant. These creatures hardly be-
tray their inner life, and it is only when we attentively observe
them that we see an occasional opening and shutting of the above-
mentioned funnels.

This group, which resembles a bed of wonderful plants, is
a riddle to all who have not examined the organisation and habits
of the low animal forms comprised within it. Thus it is ne-
cessary to mention at least the most important facts relating
to the structure and development of these animals; all the more
because lately the Tunicata have played a great part in the
scientific discussion as to the origin of the vertebrate animals,
including man.

- 43 -

If we open one of the large -white lumps (Phallusia ma-
millata) lengthwise, we see that the coarse external cartilagi-
nous coat or mantle contains a second much more delicate sack,
connected with the first in two places corresponding with the
visible external openings. The external coat is principally formed
of a substance very similar to the so-called cellulose, the mem-
branous matter of vegetable cells and once believed to be it.
The inner sack opens from the orifice at the end into a large
cavity containing the gills, the sides of which are coated with
a ciliated sort of trelliswork. At the bottom of this cavity is
the true mouth, into which small particles of nourishment are
conducted together with the water, by means of the action of
the fringes of the gills. The intestines, which are wound into
a kind of ball, lie, together with the organs of circulation and
generation, at the bottom of the inner sack, and the excretions
are emptied through the lateral opening in the body, which
also serves as a duct for the products of generation and for
the ejection of water from which the air is exhausted. A nerve-
ganglion, with radiating nerve-fibres, lies near the orifice into
which the fresh water is received.

The Ascidians , a group of the Sea-squirts, are almost all
adhesive animals, and either remain single , like the above-
mentioned Phallusiae, which are generally the largest species,
or they form colonies in which the individuals are connected
by roots (social Ascidians, for instance Clavellina). The com-
posite Ascidians form a third group. These animals are imbed-
ded in a common sack and arranged in a certain manner. To
this group belong the rind-like crusts seen on the rocks of
the tank, in which one can distinguish with the naked eye the
pretty little round animals, like rosettes , gathered round a
common excretory vent. Till now only one kind of unattached
swimming Ascidian is known, the Pyrosoma, a hollow gela-
tinous tube, shaped like a fir-cone , upon which the single
animals stand up like the little pegs on the barrel of a musi-
cal box. They belong to the pelagic animals which cause the beau-
tiful phosphorescence so often observed in the sea. This creature
is very seldom found in the Aquarium , for it is one of the
rarest and least unterstood animals in the Gulf.

A discovery made by the Russian zoologist Kowalewsky has
connected the history of the generation of the Ascidians with
that of the origin of the vertebrate animals. That naturalist
observed th'at from the eggs of the ascidians were developed
unattached swimming larvae provided with a moveable oar-tail

_ 44 -

and temporarily with an organ that, in its position, had the
greatest resemblance to the corda dorsalis, or spinal-chord of
the vertebrate animals (fishes, reptiles, birds, mammals, and such
like). This organ is an elastic cartilaginous string, along which,
in the animal in question, is laid the spine and its marrow,
and which, in the lowest form of the vertebrates, the lancet fish,
Amphioxus) remains for life, but is lost in the larvae of the
Ascidians during the retrograde transformation by which the
unattached larva becomes a fixed ascidian. The conclusion
drawn from these facts is in harmony with the scientific theory
according to which every individual, during development, passes
through a series of forms inherited from its ancestors during
the course of the earth's history. Just (to choose a more fa-
miliar example), as it is deduced from the fish-like shape and
organisation of the tadpole , that fishes were the ancestors of
amphibians, or, which is the same thing, that frogs originate in
fish-like vertebrates ; so, from the temporary appearance of the
spinal chord in the larvae of the Ascidians, it is deduced that
these animals are connected with the vertebrates by a common
original form. This theory, however, cannot yet be regarded
as a scientific fact, the difficulty of examination being so great;
and lately another theory has been opposed to it, according to
which the ancestors of the vertebrates are rather to be looked for
in animals like the higher worms or annelids in the Aquarium.
All the Ascidians are hermaphrodites, that is animals which
unite both sexes in one individual. Besides sexual generation
which produces unattached swimming larvae from impregnated
eggs, there exists in this group an unsexual generation by bud-
ding, to which the colonies owe their origin.

Opposed to the Ascidians as adhesive or attached animals, are
the Salpae as swimming animals. Their delicate transparency
shows them at once to be pelagic animals, which, like jelly-
fish, live in the open sea, and are carried, together with the
other representatives of the pelagic world, by winds and cur-
rents to the coasts, where they are often caught by thousands
in the fishermen's nets, -a very unwelcome catch indeed.

All the year round, but especially in Spring and Autumn,
salpae are brought to the Aquarium, where, like other pelagic
animals, they are exposed in separate glass vessels.. It will not
be difficult for the spectator, guided by the following remarks,
to make himself acquainted with the general construction of a

- 45 -

salpa, especially if he have before him one of the larger kinds,
for example, the Salpa maxima Africana. The outer part
of the long barrelshaped body forms, as in the Aseidians, a
tunic or sack, at each of the two ends of which there is a large
orifice. The animal swims with its fore- end first by taking up
water through the front orifice and letting it stream into the
hollow of its body, across which the gills are stretched like
a ribbon. As soon as the body is filled with water, the front
orifice closes, the muscular girdles that span the body contract,
and at one stroke drive the water out of the back orifice, thus
impelling the animal forward , which , one might say , moves
by swallowing. Near the hind-part of the body is noticed a
round reddish-brown organ , the intestinal-ball , which is led
to by a mouth- orifice situated at the bottom of the cavity con-
taining the gills. In front of the intestine lies the transparent
gourd-shaped heart, which, in this animal— a remarkable fact-
contracts alternately in diverse directions, so that the circulation
of the blood is periodically reversed.

The development of the Salpa is of great interest for natu-
ralists. The poet Chamisso , who was at the same time an
enthusiastic zoologist, observed during his journey round the
world that in the Salpae "'the daughter never resembled her
mother, but her grand-mother, " as he expressed himself; that
is, that in one species two different forms regularly alternated,
the first consisting of a chain of several salpae, while the se-
cond consisted of independent individuals. Later research has
entirely confirmed this " change of generation " in the salpae,
and discovered new details. In the Aquarium are frequently
to be found both chains and single salpae near together; the
first are often of considerable length, or strung into a wreath.
All the members of such a chain are exactly similar in struc-
ture, and develop into hermaphrodites. From their eggs, how-
ever , issue not chainsalpae but separate individuals , which
are distinguished from their parents not only by certain dif-
ferences of structure , but also by the fact that they never
produce eggs. Instead they generate, on a special germ-stock
in the vicinity of the intestinal-ball, interior buds, which are
seen, even at a very early stage, to be little chain-salpae, and
are born as such so soon as they attain a certain size. The
germ-stock produces several of these chains. Like the Pyrosoma
among the Aseidians, the Salpae also belong to the phospborent
animals, and it is from the intestinal -ball that the most brilliant
light radiates.

- 46 -

Fislies.

Fishes, the only vertebrates (with the exception of the tor-
toises) that we have in the Aquarium , are distinguished by
such well-known characteristics , that , notwithstanding the
variety of their shape, they will hardly ever be mistaken for
members of any of the other large divisions of the animal
kingdom. Neither the mollusks and crabs , nor the worms .
sea-urchins, or corals, have forms resembling those of fishes,
and. having remarked that the falsely so-called inlcfish — sepias,
calmars and such like -are not fish, but mollusks; and that the
snake-like eels, flat soles and roaches, are true fishes, we think
that we have resolved all doubt as to what is a fish and what
not, for all other examples are at once recognised.

As the fishes in the Aquarium, like the other animals, are
not arranged in systematic sequence, but according to biological
principles , in which similarity of habits and habitat are the
chief things regarded, so as to offer to the animal in confine-
ment environments as natural as possible; — we think that we
ought to adhere to the same arrangement in our descriptions.
We begin, therefore — keeping separate the two large divisions
of the bony and the cartilaginous fishes— with those of the bony
fishes that pass their lives at the bottom of the sea , where
they lie in ambush for their prey, half buried in the mud or
sand, and very seldom, and that awkwardly, swim about. We
include these fishes under the head of ground-fish. To these
belong : The Star-gazer (Uranoscopus scaber) , an ugly ,
muddy-brown fish, with a thick clumsy head and wedge-shaped
body diminishing towards the tail. Its small dull eyes are pla-
ced far back on the skull , and like the bow-shaped mouth,
turned upwards. It lies almost always buried up to the head
in the sand , and amuses the hours of patient waiting by a
peculiar sort of game. That is, it protrudes and waves about a
long worm-like ribband or tongue which grows within its lower
jaw. This strategem decoys the little fish playing near, who,
trying to catch what they believe to be a worm, are pounced
upon and seized by the greedy Star-gazer. When this fish
is disturbed it swims about and moves its broad caudal fins
like a pendulum, at the same time frequently putting out its
tongue. In a few minutes it falls plump to the ground ; and
immediatly buries itself in the sand by the shovelling movements
of its pectoral fins. It pursues the same manner of life in its

- 47 -

natural place in the muddy shallows of the sea. It is very
frequent in the Gulf of Naples and is found in the market,
though very little prized.

A similar picture is afforded to the visitor by the iceevers, Tra-
chinus, of which many species, the T. draco, the T. vipe-
ra, and others, are to be found in the Gulf. These are slender
fish, pressed sideways, with metallic-blue, lively eyes, and spiny
dorsal fins and gill-covers. "When brought into the Aquarium
they fall to the ground as soon as the first excitement is over,
and in a few seconds are buried in the sand, nothing remaining
visible but their eyes and mouth. When fed, they dart with
equal rapidity from their concealment and snap up their food
(little dead fishes) before it falls to the ground. At the same
time, and also when excited, they erect their fins, the spines
of which are rightly feared, for a \vound caused by them often
results in violent inflammation, and for this reason the fishermen
handle these fish with caution, and break off the spines before
carrying them to market. Perhaps the brilliant eyes of these
fish, which, like those of the chamelion, can move in different
directions independent of each other , serve as a decoy in a
similar manner to the tongue of the Stargazer.

This principle of a decoy-apparatus is interestingly carried
out in the Devil-fish or Angler (Lophius), probably the ugliest
monster of a fish to be found in the Mediterranean. Almost
three fourths of its body seem to be absorbed by its flat mon-
strous head and enormous mouth, the grinning jaws of which
show a row of hooked teeth. Clothed in a dirty-brown skin,
this beast lies half-buried in the sand, and stares upward
with its dull and glassy eyes, the fringe of barbels on its chin
flapping at every breath it draws. Sometimes it elevates its
foremost reversed, flexible dorsal fins and lets the fringes at their
edges play in the water as bait. Thus the Devil-fish is a living
angle, its little barbels and fringes being so many decoy-
baits for curious fish , and its gigantic mouth, always ready
to close with a snap, a trap from which there is no escape.

This creature lives in the mud in the middle deeps of the
gulf, and often reaches an immense size. Unfortunately it can-
not endure confinement, for it refuses all food, and seems to
be unable to exist out of the gloomy retreats of its natural
habitat. The visitor therefore will not always find a specimen
of this fish in the Aquarium, particularly as the larger examples
seldom reach the Station alive.

In the same tank with the Star-gazers and "Weevers, will

- 48 -

almost always be found several examples of tlie soles. The
side-swimmers or flat fishes (Pleuronectidae) to which the
soles belong , are a very singular group. Their bodies are
twisted sideways from right to left, and the head so turned
that both eyes are on the same side. Then the two sides are
entirely different in colour and skin, for the one turned down-
wards is white, like the bellies of many other animals, while
the upper side , on which are the eyes, is always of a dark
colour, and has, besides, the power of changing its colour to
that of the ground. Many of these fish can imitate the white
pebbles strewn in the grey sand, by causing similar light spots
to appear on their dark skins. This power of imitation greatly
protects the fish, and it is not always easy to see them in the
tanks. They are first betrayed by their protruding opalescent
eyes, which they can move singly in all directions and thus
command the whole neighbourhood. The sole catches its prey,
consisting of the smaller fish that also live on muddy bottoms,
by impelling its body forward with lightning-like rapidity.
The sole swims very actively , gracefully undulating its flat
body, and always turning the side on which are the eyes upper-
most. When it wishes to bury itself a few strong strokes with
its dorsal fins are sufficient to throw up a quantity of sand
which falls back upon its body; when it again lies on the watch,
immoveable for hours together.

Flat fish increase in an extraordinary manner, which fact is
partly explained by the natural protection afforded them by
their power of imitating the colour of surrounding objects. They
also form a large part of human economy, for all kinds have
excellent flesh not easily spoiled, and can therefore be imported
far into the interior. Many kinds attain an enormous size. In
consequence, they are an important article of commerce in the
North. Germany, England, France, Holland and Denmark con-
sume immense quantities. Imports to the value of 80,000 pounds
sterling are annually brought to London alone from Holland,
and this is at most the fourth part of what that city consu-
mes. In Italian markets flat fish are among the commonest
and most highly prized. They are fished in different ways,
sometimes with the harpoon and drags , sometimes with the
angle and ground-lines.

The principal flat-fish are the turbot, sole, flounder, plaice
and dab. Only the smaller kinds can be accommodated in the
Aquarium; the Sole (Solea vulgaris), the Turbot (Rhombus
maximus), and similar kinds are usually to be found.

- 49 -

From these ground-fish, in the strictest sense of the word,
there is only a step to such fishes as select the crevices and
hollows of rocky coasts for their place of abode , when they
usually lie in wait for prey in a similar manner to the fish
before described. To this class belong the curious Dragon-heads
(Scorpaena), clumsy fish with thick heads and big mouths,
large spiny fins and peculiarly developed skin-appendages, in the
form of little ragged, feathery leaves and spines. These fish
jam their bodies into the corners of the rocks, and can so ex-
actly imitate the colour of the rocks that any one not aware
of this power may stand some time before a tank full of Scor-
paenae before seeing one. In the dark corners, many resemble
a fragment of rock overgrown with delicate plants so perfectly ,
that this faculty alone must to a great degree protect them
from their enemies and enable them to surprise their prey.
We find this principle of protective imitation in a great num-
ber of animals ; it is so with the inhabitants of the desert,
which are almost all yellow like the sand; and with the white
polar and alpine animals , some of which — for example the
Snow-hen , — even change their coat according to the season.
It is so with the transparent Medusae and pelagic animals of
the ocean, whose transparency protects them from pursuit. In
some animals, the principle is carried out by their resemblance
to plants, or to animals better protected than themselves, either
by weapons or poisonous glands , or by their insignificance.
Certain flies imitate the habitus of bees and wasps, and trop-
ical butterflies imitate those of their relations who are better
prepared than themselves for the struggle for life. This inter-
esting phenomenon is called " mimicry, " and it has been
proved to exist in marine animals of very different classes. It
is a striking proof of the theory of the gradual transformation
of animals and vegetables by natural selection of better o?'
ganized forms.

Akin to the Dragon-heads, in its manner of life, is the Go-
by (Gobius niger), a little black ground-fish of clumsy form,
which always lies at the bottom of the tank, usually in some
rocky cavity, a bunch of algae, or such like. It is, however,
fonder of moving than the Scorpaena. In the sea , during
spawning time , it leaves its hiding-place and digs a roomy
dwelling among the roots of the sea-weed, in which it drops
its eggs. The male is the architect, and lies at the entrance
of the nest, enticing the female to approach. When the latter
has laid her eggs , the male immediately impregnates them,

4

- 50 -

and later on guards the brood for about four months, courage-
ously defending it against every foe. When the female has
made numerous visits, the nest is enlarged and provided with se-
veral exits. During the spring-months the laying of the eggs,
and their bold defence by the male, may very often be ob-
served in the Aquarium.

The numerous varieties of mudfish (Blennius) are small ,
bold, voracious fish, which, in spite of their awkwardness in
swimming, are very lively. They inhabit the algae-grown re-
gions of the rocky coasts in shoals. They may be seen pursuing
each other among the rocks and sea-weed. When danger ap-
proaches they disappear into some corner quick as lightning.
They are very curious, tasting everything that comes in their
way , and they molest all inoffensive animals. They tear off
the heads of the annelids, attack the eyes of crabs and fishes,
and pull the anemones till they die.

The largest and most beautiful of this species is the Butterfly
fish (Blennius ocellaris), which has large erectable dorsal
fins with a dark blue spot in the middle.

Passing from these ground fish to those which move freely
through their crystal element , we come first to some good
swimmers, who, however, still cling to the bottom of the water
and near the coast , where they sometimes remain quiet and
sometimes swim about. Of this class many species of Gur-
nards (Trigla) and Flying -gurnards (Dactylopterus) live in
the Gulf. The first are distinguished by a peculiar growling
noise which they make when taken out of the water. This noise
is produced by the friction of certain parts of their hard gill-
cases against neighbouring parts. Their movements when on
the ground are also curious, for they run along. on the ribs
of their pectoral fins, which are unconnected by any skin, like
crabs run on their legs. These pectoral fins are like splendidly
coloured wings, and by their aid the fish can spring out of the
water. They are very voracious, and have enormous mouths.

The Flying-Robin (Dactylopterus volitans) is a beautiful
creature, which uses its strongly developed pectoral fins like
real wings. These fish live in swarms sometimes creeping on
the ground, at others swimming about in all directions. They
rise with a noisy beating of their fins to a height of sixteen
feet above the surface of the water, and after a flight of some
100 feet, fall back, to repeat the same sport. Frequently se-
veral swarms follow each other, and are seen rising and sinking
in rapid sequence. When such swarms take a decided direction

-Sl-
it is certain that they are pursued by some enemy. In the
neighbourhood of the coast they attract sea-birds, which hunt
them from above. They are less persecuted by men, for their
flesh is hard and tasteless. When taken they also growl like
the Gurnards. In the Aquarium they are only periodically seen.

In similar swarms the Red mullet (Mullus barbatus) fre-
quents the muddy bottom , rich in animal organisms , of the
ocean, where they eagerly seek for food with the two sensitive
barbels on their jaws. In the Aquarium one can observe the
play of these two feelers; sometimes they slowly and carefully
search the mud , and at other times move with great rapidity
in all directions, or are drawn back into the folds of the jaws.
The Red Mullet was highly prized by the Romans, and incred-
ible sums were paid for a large fish. Seneca and Juvenal
relate that some were worth from 6 to 8000 sestertia. The
fish were also presented alive in glass dishes to the guests ,
and allowed to die in the "hands of women, who delighted in
watching the beautiful play of colour on the scales. The red-
mullet is still highly valued in all Italian markets, but is not
very dear.

As an inhabitant of the rocks, we have still to mention the
Eel, of which species the great Conger-Eel (Conger marinus)
and the Muraena (Muraena helena) are to be found in the
Aquarium the whole year round. The other species frequenting
the Gulf, such as the Conger myrus and Ophisurus, are
rarer guests, and only occasionally to be found. In the tank
containing the eels and muraenae , these creatures are found
in various situations ; some swimming about with beautiful
undulations of their bodies; others lying half hidden in vessels
and jars placed in the tank on purpose, only their heads and
rapidly breathing gills protruding from the orifices. In a na-
tural state the crevices of the rocks serve as similar hiding
places. The conger-eel is a gluttonous fish which often attains
the enormous length of more than ten feet, and even in the
aquarium, owing to its phlegmatic habits and excellent appetite,,
it becomes a splendid example of the species. It is very soon
tamed, learns to take food from the hand of the keeper, and
never refuses the young of its own species. It is common in
the market and not dear.

The Muraena is distinguished by the beautiful marking of
its body and the absence of pectoral fins. It amiably shares
the jars with the eels, and we often see two or three animals
in the same vessel , so that it is difficult to understand how

- 52 -

they find room. Its beautiful snake-like motions, splendid co-
lour, high dorsal-fins, and the expression of its head, with
glassy eyes and wide-stretched jaws, give the Muraena a very
peculiar appearance, which involuntarily attracts the attention
of the spectator. It is well known that the Romans considered
these fish a great luxury , and built large tanks in the sea
for them, so as to have a supply always on hand. Pliny relates
that a certain Hirius , on the occasion of Caesar* s triumphal
entry, laid before his guests 6000 of these fish. Crassus pos-
sessed a large muraena, of which he was very fond; he put
a golden collar round its neck, and is even said to have wept
when it died. It is told of Vedius Pollio that he punished
several guilty slaves by throwing them as food to his muraenae,
having heard that human flesh made those fish very delicate
eating. At present the Muraena is highly valued, and there is a
large market for the fish at Pozzuoli. They are caught iu baskets
or with the line. At such times they offer violent resistance,
biting savagely, and, being very slippery, are difficult to hold.
Fishermen are afraid of their bite and think it poisonous, but
no doubt it is only the shape of their sharp and crooked teeth
that produces wounds difficult to heal. They endure confine-
ment in the tanks of the Aquarium for years together , and
like the eels, can be tamed to a certain degree.

Very curious little animals, not only among ground-fish, but
any fish, are the Sea-horses and its relations, which under the
name of LopJwlrancJiii are classed in a particular division.
Almost everyone who has visited a marine town is acquainted
with the common Sea-horse (Hippocampus) which is found
dried in the fish- markets, for its case or coat is so hard that
the shape remains almost unchanged. The habits of this little
creature, which is common in the Gulf of Naples, are extremely
attractive; everything about it is strange, even its shape, which
closely resembles that of a chess-knight. They are best off when
kept in a tank where branches of corals or tube-dwelling
.worms afford points of support around which they can cling,
according to their habit, with their finless , prehensile tails.
The tank containing the worms is therefore appointed for their
habitation. Here they may be seen in all possible positions ;
swinging on the stems of the worm-tubes, and looking about
with their small qnick eyes for the minute animals that people
the outside of the tubes. When they swim they rapidly move
their little fins , and float up and down with graceful move-
ments, turning and bending in all directions, either pursuing

- 53 -

each other or swimming in pairs , at the same time twisting
their tails round each other and playing all sorts of pretty
tricks. In pairing time (autumn) their motions are very lively,
and a couple are often to be seen swimming about and caress-
ing each other or hanging in loving companionship on the
tube of some marine worm. The manner in which they nurse
their progeny is equally curious. As soon as the female lays
her eggs they are received by the male, who carries them about
with him in a pouch under his tail until the little things are
capable of independent existence. When their lively movements
begin to irritate the male , he endeavours to rid himself of
them , repeatedly bending his tail near the place where the
pouch is. At every bend he makes the pouch opens, and a num-
ber of the little animals, which look like notes of interrogation,
escape and immediately begin to swim about; they are then
about half an inch long.

The sea-horses are of no importance whatever to mankind,
and it seems that they have few or no enemies in the sea; at
least in the Aquarium, where they are kept together with all
kinds of animals, they remain entirely unmolested. Other kinds
of Lophobranchii are the Sea-needles (Syngnathus, Nerophis,
and Siphonostoma). The last inhabits meadows of seagrass;
and in form and colour imitates to perfection the decaying lea-
ves (mimicry).

The true swimming fish to which we will now turn our at-
tention, are principally the kinds familiar by their shape even
to the non-scientific visitor. They spend the greater part of
their lives in swimming or floating, thus proving that they are
more or less master of the element in which they live. Yet
even some of these are, by habit and the food they eat, bound
to the configuration of the coasts, and there have their settled
abode; while others rove more freely through the ocean, espe-
cially the pelagic fish , and are entirely independent of the
shore or the bottom of the sea.

We will first notice the coast fish and, before all, the Wrasses
or Labroidae, a species distinguished for splendour of colour
reminding one of the tropics , and deriving their name from
their thick protrusive lips. To this species belong the gay
Labrus and Crenilabrus, and the smaller Julis; all lively
fish that frequent precipitous coasts rich in algae, and are to be
recognized by their peculiar way of swimming by starts. Of
the first-named and larger kind the pretty Labrus festivus
is very interesting from the care which it takes of its young,

- 54 -

and the bold defence of them by the male. The small Julis
(Julis Giofredi, vulgaris and turcica) are as pretty and
swift in their motions as they are richly coloured, and a great
ornament to the Aquarium. The voracity with which they fall
upon anything that is thrown to them , and their impudent
curiosity, are very amusing. They fight hard for every morsel,
and each tries to snatch a bit with his pointed and fine toothed
snout. They glitter splendidly in the sunshine, their eyes shi-
ning like jewels. They are very sensitive to a low temperature,
and every evening go to bed in the sand at the bottom of their
tank, so that a night-visitor to the Aquarium will only see here
and there some small head protruding. On cold winter days
they also remain buried in the sand, and at all times , if in
danger, disappear like lightning. The larger kinds of Labrus and
Crenilabrus may often be seen resting against some rock, a
habit in which there is still a trace of the ground-fish.

Similar to these is the Easor-fish (Xyrichthys novacula),
which conducts itself exactly like the Jiff's; and the small Monk-
fish (Heliastes chromis) which haunts steep coasts in so-
ciable troops.

Contrasted with the liveliness of these smaller fish, is the
phlegma of the Sea-perch, the largest of which, Giant- perch
(Serranus gigas) is not only the most majestic, but also bears
confinement best. This fish delights in floating for hours in
one spot, generally near the stream of water which runs into
the tank ; sometimes it places itself immediately beneath the
stream in a vertical position and allows the fresh aerated water
to pour into its wide open jaws and gill- covers. When alarmed
it darts away under some arch in the rock-work , and with
equal rapidity rushes at its prey, which it unfailingly catches.
Its whole behaviour proves it to be a prudent, retiring creature,
fond of safe hiding places. Under the name of Cernia this fish
is one of the finest table-fish in the Italian market , and com-
mands a high price.

The little writing -perch (Serranus scriba) so called from
the marks on its gill- cases which look like handwriting , is
distinguished for its beautiful colour and resembles its relatives.
This species belongs to the few hermaphrodites found among
fishes.

Much more lively than the above fish are the ivolf- perches
(Labrax lupus) which traverse in company the largest tank
in all directions. The wolf-perch is a voracious fish found both
in the Atlantic and the Mediterranean. The ancients were well

- 55 -

acquainted with this fish. It often attains a length of more
than three feet, and is one of the finest table fish (Branzin,
Spinola). It usually haunts the coast, for it prefers shallow
water, and often enters the mouths of rivers. In stormy wea-
ther perches approach in shoals in order to catch the mollusks
torn from the rocks by the breakers. They are caught with
the line , and the larger kinds offer violent resistance when
taken. In the Aquarium, they live and propagate for years,
but till now the young have never fully developed

To the commonest fish in the Gulf belong the different spe-
cies of the genus Mugil (mullet). They are easily recognised by
their slender silver-grey bodies and the peculiar form of their
mouths ; the thick upper lip has a gap into which fits a pro-
tuberance on the under-lip. These fish come near the coast
in shoals, and chiefly feed on soft, decayed material. In the
Aquarium they prefer the algae and slime which cover the
rocks, and decayed animal and vegetable matter, so that they
are very useful as scavengers. Their flesh is very good and
tender, and, being also plentiful, they are one of the commo-
nest table-fish (Cefalo).

Many fish of the same kind are almost always to be found
in the Aquarium, but so little is known of their habits, when
in their natural state, that it is scarcely possible to enter into
detail, so we will be content with mentioning their names,
adding a few remarks to the most interesting. First are the
different species of Bream, which, having well-tasting flesh,
are largely fished and highly valued in the market. The sack-
bream (Pagrus^ red-bream (PsLgellus). gold-stripe (Box) and
similar small kinds live together in one tank, and feed on small
crabs and other animals; also on vegetable matter. Then come
the larger goat-bream (Sargus), snout-bream (Maenaj, and
the rarer blade-bream (Cantharus), which has hitherto been
represented in our tanks by a single individual that has lived
there for several years and is the oldest fish we have. The
most valuable are the gold-bream (Chrysophrys) and tooth-
bream (Dentex) , very beautiful fish, with shining marks on
their round backs. The first is caught in all parts of the Me-
diterranean, and also in brackish inland-seas and lagoons, where
they go to hunt shellfish, for which reason the latter are used
as bait in fishing. The Romans cultivated these fish in ponds
and in Lake Lucrine. The tooth-bream is the largest of all, often
attaining a length of three feet, and weighing more than 20
pounds. These fish are terrible brigands and often snatch fish

- 56 -

out of the very net. In the Aquarium they are very lively ,
and fond of swimming in company.

Compared to the glittering breams, the Sea-raven (Corvina
nigra) is remarkable for its dark brown colour. It is a peace-
able fish , always keeping close to its fellows , and r head
downwards , seems to be thoughtfully examining the bottom
of the tank.

Of the PlectognatMj so rich in strange forms of a tropical char-
acter], which may be known to the visitor in the globe-fish
seen in Museums of Natural History, we are acquainted with
only two species that inhabit the Gulf of Naples : the moon-
fish or swimming -head (Orthagroriscus mola), and the fca-
lista (Balistes capriscus). The first is, till now, one of the
greatest rarities in the Aquarium , and scarcely ever outlived
its imprisonment more than a few days, so that we can report
nothing interesting as to its habits. We have become much
better acquainted with the Balista, of which we have always
specimens from spring to autumn. This fish is full of interest.
Its very shape, its one sided and out of all proportion short
and thick body, at once excites attention, and its brilliant blue
eyes, as well as its narrow pointed mouth armed with a few
closely-set incisors, heighten the singularity of its appearance.
It is a lively, curious, sociable fish, which, however, only fully
shows its nature during the summer months , for it is very
sensitive to cold, and regularly sinks to the bottom of the tank
when winter commences. It lives on shell-fish and crabs, which
it breaks with its powerful teeth, making such a noise in doing
so that it can be heard through the glass of the tank. It snatch-
es food from the very jaws of the large tortoises that share
its tank , and attacks the eyes of lobsters and craw-fish , so
that these animals cannot be kept in the same tank.

The Balistae have given us a few remarkable proofs of their
power of discrimination, which may be briefly related here. One
day a dying shark (Carcharias glaucus) , about five feet
long, was put into the large tank containing the Balistae, where
he died a few minutes after. Scarcely did the Balistae catch
sight of the animal when they fled in mad fright, and hid in
the darkest holes and crevices cf the rock- work, whence they
cast shy glances, changing their colour the while, on the dying
monster. They had recognised their deadly enemy at a glance,
and showed their terror in— for fishes— an extraordinary manner.
Another case was that of a single Balista which the keeper had
repeatedly tried to catch , in vain. Each time it slipped into

- 57 -

a certain hiding-place. Whenever it saw the keeper appear with
his net above the tank, it retreated to its corner, while other
people it regarded with the greatest calmness and curiosity ,
swimming about on its side at the top of the water.

We have now arrived at the true pelagic swimmers , the
mackerel. Like the storm-birds and frigate-gulls that spend
their lives suspended above the immeasurable plains of ocean,
these fish traverse the high seas, only approaching the coast
periodically, when (like the tunny) they become the objects of
extensive fishing. — All attempts to introduce these shy and
sensitive fish into the Aquarium have failed. We shall never
be able to keep either the tunny or its nearest relative, the
sword-fish, in our tanks, for they cannot endure the slightest
abridgment of their liberty. They all become frantic and die
within a few hours , and only a little fork-mackerel , the
beater (Lichia glauca), has, like the Balista, become a re-
gular summer guest in the Aquarium. It is an extremely pretty
fish, with its slender body shining like pure silver, and its
restless activity.

A pelagic fish akin to the true mackerel, which roves sol-
itary in the high seas and is seldom brought to the Aquarium,
is the St. Peter's fish (Zeus faber). It derives its name from
the legend that out of this fish's mouth St Peter took the piece
of money; the people say that the two dark spots on its sides
are the impression of the saint's fingers. It swims slowly about,
waving its large fins , but refuses all nourishment, and soon
turns on its side and dies. It is valued as. food in all European
markets.

The second order of fishes of which we have yet to speak,
includes the cartilaginous fishes to which belong the sharks and
roaches. Of this group the Aquarium contains almost exclu-
sively the ground-fish, which reveal very little of their habits
to the visitor. We will therefore chiefly confine our description
to the pecularities of their organisation and development, and
only in the second place mention their very monotonous habits.
Let us first take the sharks.

The mention of this name usually arouses in the non-scien-
tific listener the idea of those sea-giants that are the horror
of sailors and all inhabitants of the coast. He is therefore no

- 58 -

little astonished when told that a fish in the Aquarium, scarce-
ly three feet long , is a shark ; and probably imagines it to
be a young, or " false " shark, We must therefore remind our
reader that the chief characteristic of the species is not gigantic
size , but a peculiar organisation ; and that , excluding young
ones, there are very small varieties of the species shark, which
have all the peculiarity of construction common to the large
varieties. In order to understand this peculiarity , as far as
visible in the living animal , we beg the visitor to look atten-
tively at one of the spotted cat-sharks that usually lie in a cor-
ner close to the glass of the large tank, and compare it with
one of the large perches. The perch has the typical scaly body>
dorsal, pectoral and anal fins, symmetrical tail, large moveable
gill-coverings , with the leaves of the gills beneath lying in
rows fastened to a bony arch, and mouth situated at the point
of the head; it has further lidless and glassy eyes, and small
nostrils. The shark, on the contrary, has no scales, but has
a rough skin like -chagrine; its tail is unsymmetrical, one side
being long, the other short. Its mouth is a large slit, set cross-
wise under the head, and its gills are fast grown to the sides
of certain pouches which lie one behind the other, and are led
to by a row of five or more openings in the skin of the neck.
Its eyes have lids which can close, and its large nostrils are
distinguished by flaps of skin. The skeleton of the shark is
cartilaginous-not bony-and the skull is a gristly capsule. These
characteristics are common to all sharks, both large and small,
and by them even an unpractised eye at once recognises the
genus as entirely different from all bony fishes.

The shark which mwe take for an example , belongs to the
genus Scyllium, of which two kinds, the Sc. catulus and
the Sc. canicula — cat-shark and dog-shark— are found all
over Europe. The first attains a length of three to three and
a half feet , the latter only one and a half to two feet, so that
this one belongs to the smallest variety. They are lazy fish
which hunt their prey at dusk and in the night, and during
the day generally sleep in a corner of the tank, rarely swim-
ming about. In the daytime they seek their food by scent, for
at that time they are half blind. They go smelling all over the
bottom of the tank, with graceful motions of their spotted bodies,
and it is only when they touch it with their noses that they find
their food. They are little less gluttonous and impudent than
their larger relatives, and their well-armed jaws can master im-
mense pieces. We have become thoroughly acquainted with their

1

- 59 -

manner of propagation. The female deposits her eggs on coral
branches, or on plants or rocks. The eggs are single square, horny,
transparent capsules, which are first white and then turn into a
yellowish brown colour; they have at each corner long twisted
cartilaginous strings similar to cat-gut, by means of which the
female fastens each egg to some object , and to effect this ,
swims round and round it while the egg is being ejected from
her body. This hanging-up of the egg is meant to preserve it
from being covered by mud or sand , which is the greatest
danger to which it is subject, except that of being destroyed
by the animals that live in the sand. The development of the
germ in the egg can be well seen through the transparent shell.
The so-called germ-spot first develops on the oval yolk , and
gradually over-grows and becomes separated from it. Later on
one can recognise the form of the little fish which is transpa-
rent as glass , and has on each side of its neck a bunch of
exterior gill-threads (temporary embryonic organs). It is con-
nected with the yolk-bag by a long string which conducts the
nourishment into its intestine. The lively undulating move-
ments of the slowly growing little animal can now be seen ;
by-and-by the gill-threads are absorbed , and later on , the
colouring and spots on the skin of the young fish gradually ap-
pear and increase in distinctness. When the young one is ready
to escape from its prison, and has consumed all the yolk, it
pushes itself head-first through one end of its eggshell where
the flakes are more loosely connected , and swims actively
about, dragging after it the remains of the yolk-bag. The eggs
and embryos are often to be seen in the Aquarium , for not
only as the Scyllii of the large tank pair and deposit their eggs
on rocks and branches, but fishermen also bring pieces of coral
and similar objects hung with shark-eggs. Just lately these
embryonic stages have become very important to science, and
comparative anatomy has very often profited by the rich ma-
terial afforded by the Zoological Station. The use of the Scyllii
from an economic point of view, is very small. Their flesh is
bad , and only eaten by the very poor ; the skin is used for
polishing, the liver for preparing oil. They commit great rav-
ages among herrings in the northern seas.

The smooth shark of Aristoteles, Mustelus laevis, is far
less often found in the Aquarium than the cat-shark , for it
can scarcely endure confinement. It is one of the most harm-
less of the race. Its blunt teeth oblige it to feed on mollusks
and other soft animals, which it finds in the deep sea. When

- 60 -

brought into a tank, it first swims rapidly about with beau-
tiful undulating motions of its silky body, but very soon grows
faint, and at last can no more rise from the ground, and re-
fuses all nourishment. The propagation of this fish is very in-
teresting, for it is one of the sharks that give birth to living
progeny. The embryo develops by means of a so-called yolk-
lag-placenta, that is, there are formed on the surface of the
yolk numerous little protuberances that fit into corresponding
depressions on the sides of the womb, and thus a connection
is maintained between the mother and the fruit similar to that
known in the mammalia. There has been frequent opportunity
in the Aquarium to witness the birth of from fifteen to twenty
young ones.

Another fish that bears living young, and forms the transi-
tion from sharks to roaches, is the Sea-angel (Squatina an-
gelus); a large mishaped fish, which like the flat fish, lives
always on the ground , and is often taken for dead by the
spectator. The sea-angel is one of the dullest and laziest fish
in the Mediterranean, and feeds on what it finds living at the
bottom of the sea. When disturbed it swims pretty quickly,
end shows the wing-like shape of its pectoral fins, from which
it derives its name. Poor people eat its bad flesh, and its skin is
manufactured into rasps, knife-handles, sheaths, and such like.

The real roaches have a flat body shaped like a plate and
all on one side. On the upper side, which is dark coloured,
are the eyes and two spouting holes that lead to the gills.
The long thin tail is usually spiny. They are all ground-fish,
and, like the sea-angel, live on the fish that inhabit the same
region.

The most interesting variety is the electric ray (Torpedo),
the electric power of which was known to the ancients. Its
flat, naked, slimy body is nearly round, and contains on each
side a large bean-shaped electric organ, consisting in numerous
vertical six-sided columns of a gelatinous substance, in which
a number of nerve-fibres , originating in the spinal-marrow ,
end in peculiar organs called nerve-end plates. The nervous
electricity is collected in this apparatus and discharged when
the fish is touched. The back is positive, the belly nega-
tive; and in order to receive a shock the visitor must touch
the fish on back and belly at once. The effect is considerably
weaker than in the South- American electric eel, but in a large
fully developed fish, is painful enough. After repeated dischar-
ges, the strength of the shock decreases. This organ is a wea-

- 61 - ; ';/.

pon of offence and defence, the fish killing or at least paralys-
ing its smaller prey by its means.

The electric ray bears living young, sometimes eight to four-
teen at one time. It is one of the commonest fish in the Gulf,
and, in spite of its bad flesh, is often found in the market. It
lives very well in confinement and there is always in the Aqua-
rium at least one fish placed in a small open tank for visitors
to experiment with.

Many other kinds of rays live in the tanks of the Aquarium;
for example, the Raja, and the thorny-ray (Trygon), but the
last is rare. The first have a rhombic body of a brown colour,
and a thin prickly tail. The Trygon is violet-black in colour
with a wing like extension of the skin and long thin tail. On
this tail there is a spike said to produce dangerous wounds.

We must still mention, while speaking of fishes, the remark-
able lancet- fish (Amphioxus lanceolatus), which has been
so much talked about of late years , and which is considered
to be the smallest and simplest form of vertebrates. This little
fish scarcely two inches long, and almost transparent, has no
fins, no bones, and no brain. Instead of a heart it has only some
pulsating vessels filled with colourless blood, and in its remain-
ing organic system , shows such a primitive formation , that
the species has been separated from true fish and placed in a
peculiar subdivision (tube-hearts, skull-less fish). But far more
on account of its manner of development than on account of
its bodily construction, this animal has attracted the attention
of zoologists, for the first stages of that development have the
greatest resemblance to those of the Ascidians. The Amphio-
xus is therefore considered to come next to the original form
of the vertebrate animals. Another theory sees in its low or-
ganisation the result of a retrograde development, and points
to its habits , for it leads a light-shunning existence in the
shallows of sandy coasts, and rather resembles a mud-inhabiti-
ting worm than a fish. It is found by thousands in sandy
places on the shores of Posillipo and similar localities on the
Gulf, and has also been proved to exist in the German Sea and
the Ocean (South- America). It can only be kept in the Aqua-
rium wben provided with a 'quantity of sand in which to bury
itself, and it only issues forth at night or when disturbed.

Besides the fishes, we have one reptile in the Aquarium ,
the Couana (Thalassochelys corticata), a Mediterranean

- 62 -

sea-tortoise which sometimes attains a length of four feet, and
weighs as many hundred pounds. It is frequent on all Medi-
terranean coast, and is found in the Adriatic as far as Trieste,
and also in the Atlantic coasts of Europe. It lives on crabs
and other small animals, and when newly caught defends it-
self bravely. Its mighty jaws are a weapon by no means to be
despised. Even in confinement it continues vicious and ready
to bite for some time. The tortoises in the Aquarium have
often fought furious battles so that it has been necessary to
separate them. In winter they become torpid and lose their
appetite. They are of very little value, for their flesh is taste-
less and their shell useless.

1

INDEX

Actinia 7,8.

Chrysophrys 55.
Cirripedia 31.

Galathea 25.

Adamsia 27.

Cladactis 8.

Gammarus 30.

Agalmopsis 14.
Alcyoniae 11.

Clathria 7.
Clavellina 43.

Gephyrea 22.
Geryonia 12.

Alpheus 26.
Alternation-of- gene-

Cockles 41.
Coelenterata 15.

Giant-perch 54.
Goat-bream 55.

ration 13.

Comatula 17.19.

Gobius 49.

Amphioxus 44,61.
Amphipoda 30.
Angler 47.

Conger 51.
Conger-Eel 51.
Coral 10.

Goby 49.
Gold-bream 55.
Gold-stripe 55.

Anilocra 30.

Corallium 10.

Gorgonidae 11.

Annelids 20.
Anthea 8.

Corkpolypes 11.
Corvina'56.

Grass -hopper - crabs

Anthozoa 7.

Couana 61.

Gurnards 50.

Antipathes 11.

Crabs 28.

Aphrodite 21.

Cranson 26.

Aplysia 37.

Crawfish 25.

alia 22.

Apolemia 14.

Crenilabrus 53.

Hav-crabs 30.

Ascidians 43.

Crustacea 23.

Heiiastes 54.

Asteracanlhion 19.

Ctenophores 15.

Helmeted-snail 37.

Astroides 8.

Cunina 12.

Hermione 21.

Astropecten 19.
Athorybia 14.
Auditory stones 26.
Axinella 7.

Cydippe 15.
Cymbulia 39.
Cymothoa 30.

Hermit-crab 26.
Heteropods 38.
Hippocampus 52.
Hippopodius 14.

Holothuria'19.

actylopterus 50.

Homarus 23.

alanus 31.

Dendfophyllia 11.

Homola 29.

Balistes 56.

Dentex 55^

Hyalaea 39.

Barrel-snail 36.
Bashful- crab 29.

Devil-fish 47.
Division of labour 14.

Hydroid-polypes 13.

Bath-sponge 5.

Dog-shark 58.

Beater 57.

Dolium 36.

nachus 28.

Beroe 15.

Dorippe 29.

Isopoda 30. *

Black-bream 55.

Doris 38.

Blennius 50.

Dorocidaris 19.

Bonellia 22.
Box 55.

Dragon-heads 49.
Dromia 29.

ellv-fish 12.
Julis 53.

Brachyura 26.

Brittle-starfish 19.

Brittle-stars 17.

chinoderms 16.

eel-snails 38.

Bryozoa 22.

Echinus 17,19.

Budding 9.

Electric ray 60.

Butterfly fish 50.

Eledone 34.

abrax 54.

Eriphia 29.

Labrus 53.

Eschara 22.

Lancet-fish 44,61.

alamajo 35.

Ethusa 29.

Lepas 31.

Calappa 29.

Eunice 22.

Leucandra 7.

Calmar 35.

Etipagu^rus 26.

Lichia 57.

Campanularia 13.

Euspongia 5.

Lion- rabs 25.

Cantharus 55.

Lissa 28. •

Carcharias 56.

Lithodomus 40.

Carcinus 29.

eather-stars 17.

Lobster 23.

Cardium 41.

Fin-snails 38.

Loligo 35.

Cassiopeia 12.

Fierasfer 19.

Lophius 47.

Cassis 37.
Cat-shark 58.

Fishes 46.
Flat-fishes 48.

Lophobranchii 52.
Luidia 19.

Cefalo 55.

Flat-Lobster 25.

Lupa 29.

Cernia 54.

Flea-crab 30.

Lysmata 26.

Cestus 15.

Flying-gurnards 50.

Change of genera-
tion 45.

Flying-Robin 50.
Forskalia 14.

Mackerel 57.

~ 64 -

Maena 55.

Prawns 26.

Solea 48.

Maja 28.
Marine worms 20.

Praya 14.
Pteropods 38.

Spider-crabs 29.
Spinola 55.

Medusae 12.

Pterotrachea 38.

Spirographis 20.

Mollusca 32.

Purple-snails 36.

Sponges 5.

Monk-fish 54.

Pyrosoma 43.

Spurt-worm 22.

Moon-fish 56.

Squatina 60.

Moss-animals 22.

Squid 35.

Mudfish 50.

adiata 15.

Squilla 29.

Mugii 55.

Raja 61.

Starfish 17, 19.

Mullet 55.

Razor-fish 54.

Star-gazer 46.

Mullus 51.

Red-bream 55.

Star-worms 22.

Munida 25.

Red-mullet 51.

Stenopus 26.

Muraena 51.

Reniera 7.

Stenorhynchus 28.

Murex 36.

Retepora 22.

Stone-mussel 40.

Musk-eledone 34.

Rhizostoma 12.

St. Peter's fish 57.

Mussel 39.

Rhombus 48.

Suberites 29.

Mussel-guard 40.
Mustelus 59.

Rib-jellyfish 15.
Roaches 57.

Swimming-head 56.
Sword-fish 57.

Myriozoum 22.

Root-crabs 32.

Syngnathus 53.

Mytilus 39.

Myxilla 7.

wack-bream 55.

Terebellae 21.

Nauplius 31.
Nerophis 53.
Nettle-cells 8.

Sagartia 8.
Sail-Siphonopho-
res 15.
Salpae 44.

Tethya 7.
Tethys 38.
Thalassochelys 61.
Thorny-ray 61.

Sargus 55.

Tiedemannia 39.

Scallop 41.

Tooth-bream 55.

ceania 12.

Scalpelium 32.

Torpedo 60.

Octopus 32.

Scorpaena 49.

Toxopneustes 19.

Onuphis 21.

Scyllarus 25.

Trachinus 47.

Ophidiaster 19.
Ophisurus 51.
Ophiuridae 17.

Scyllium 58.
Sea-anemones 7.
Sea-angel 60.

Trepang 19.
Trigla 50.
Tritonium 36.

Orthagoriscus 56.

Sea-cucumbers 19, 17.

Tritons-horn 36.

Os sepiae 34.

Sea-feathers 12.

Trygon 61.

Ostrea 41.

Sea-hare 37.

Tubularia 13.

Oyster 41.

Sea-horse 52.

Tunicata 42.

Sea-mouse 21.

Turbot 48.

Sea-needle 53.

achygrapsus 29.
Pagellus 55.
Pagrus 55.

Sea-perch 54.
Sea-poulp 32.
Sea-raven 56.

Uranoscopus 46.

Palaemon 25.

Sea-rod 12.

Palinurus 25.

Sea-spider 29.

elella 14, 15.

Partition 9.
Pecten 41.

Sea-squirts 42.
Sea-tortoise 62.

Venus-girdle 15.
Vermetus 35.

Pelagia 12.

Sea-urchin 16, 17, 19.

Virgularia 12.

Peneus 26.

Sepia 34.

Pennatulae 12.

Serranus 54.

Phallusia 43.

Sertularia 13.

eevers 47.

Phronima 31.
Physalia 14.
Physophora 14.

Sharks 57.
Shellfish 39.
Shore-crabs 29.

"Whirlpool-worms 22.
Wolf-perch 54.
Wool-crab 29.

Pinna 40.
Pinnotheres 40.

Shrimps 26.
Side-swimmers 48.

Worm-snail 35.
Wrasses 53.

Pisa 28.
Planariae 22.
Pleurobranchus 38.
Pleuronectidae 48.

Siphon-jelly-fish 14.
Siphonophores 14.
Siphonostoma 53.
Sipunculus 22.

Writing-perch 54.
Ayrichthys 54.

Polypes 7.

Smooth shark 59.

Portunus 29.

Snails 35.

Precious coral 10.

Snout-bream 55.

eus 57.

Protula 20.

Sole 48.

Zoea 31.

1

Aquarium Neapolitanum.

(Atlas).

Spongiae Tab. 1

Coelenterata „ 2 — 7

Echinodermata „ 8 — 9

Vermes „ 10-12

Crustacea „ 13-17

Mollusca ,18-26

Tunicata , 27-28

Pisces „ 28-46

Reptilia 47

Aquarium Neapolitanum

1. Sycandra capillosa. 2. Acanthella.

3. Tethya lyncurium. 4f Euspongia officinalis.

5. Axinella.

G. C. J. Voemaer del. Werner 4 Winter, impr.

Aquarium Neapolitanum,

6.

1. Cereactis aurantiaca.

3. Cerianthus rnetnbranaceus.

5. Dendrophyllia ramea.

C. Merculiano fee.

2. Anemonia sulcata.

4. Gladactis Costae.

6. Astroides calycularis.

Werner & Winter, impr.

Aquarium Neapolitanum,

3.

1. Isis neapolitana.
3. Corallium rubrum.
5. Gorgonia verrucosa.

C. Merculiano fee.

2. Pennatula phosphorea.

4. Antipathes larix.

6. Alcyonium palmatum.

Werner A Winter, impr.

Aquarium Neapolitanum,

1- 2.

1. Cotylorhisa borbonica. 2. EJiizostoma pulmo.
3. Pelagia noctihica. 4. Titna flavilabris.

5. Car marina hast at a. 6. Cosmetira punctata.

7. Charybdaea marsupialis.

C. Merculiano fee.

Werner A Winter, irapr.

Aquarium Neapolitanum,

1. Aglaophenia pluma. 2. Eudendrium ramosum.

3. Antennularia antennina. 4. Tiibularia larynx.

5. Pennaria Cavolinii.

C. Merculiano fee.

Werner A Winter, impr.

Aquarium Neapolitanum,

6.

1. Diphyes Sieboldii.
3. Forskalia contorta.
5. Porpita mediterranea.

2. Physophora hydrostatica.

4. Velella spirans.

6. Hippopodius neapolitanus.

C. Merculiano fee.

Werner <fe Winter, impr.

Aquarium Neapolitanum,

7.

1. Eucharis multicornis.
3. Cestus Veneris.

2. Beroe ovata.

4. Callianira bialata.

C. Merculiano fee.

Werner ft Winter, impr.

Aquarium Neapolitanum,

1. Astropecten aurantiacus.
3. Luidia fragilis.
5. Asterias glacialis.

C. Mercnliauo fee.

2. Echinaster sepositus.
4. Ophioderma longicauda.
6. Antedon rosaceus.

Werner A Winter, irapr.

Aquarium Neapolitanum,

1. Sphaer echinus granularis.
3. Echinocardium cordatum.
5. Holothuria tubulosa.

C. Merculiano fee.

2. Dorocidaris papillata.
4. Cucumaria cucumis.
6. Stichopus reyalis.

Werner A Winfcr, impr.

Aquarium Neapolitanum,

10,

1. Bonellia viridis.

3. Phascolosoma.

5. Branchellion torpedinis.

C. Mercaliano fee.

2. Sipunculus nudus.

4. Cerelratulus marginatus.

6. Carinella annulata.

Werner & Winter, impr.

Aquarium Neapolitanum,

11

1. Spirographis Spallatizanii. 2. Arenicola GmbH.

3. Myxicola infundibulum. 4. Onuphis tubicola.

5. Terebella. 6. Protula intestinum.

7. Serpula uncinata.

C. Merculiano fee.

Werner 4 Winter, impr.

Aquarium Neapolitanum,

12.

1. Alciopa Cantrainii.

3. Polynoe squamata.

5. Nephthys scolopendroides.

7. Flustra papyrea.

C. Merculiano fee.

2. Halla parthenopea.
4. Aphrodite aculeata.
6. Retepora cellulosa.
8. Myriozoum truncatum.

Werner & Winter, impr.

Aquarium Neapolitanum,

13.

1. Scyllarus latus. 2. Gebia litoralis.

3. Palinunis vulgaris. 4. Galathea strigosa.

5. Homarus vulgaris.

C. Merculiano fee.

Werner A Winter, impr.

Aquarium Neapolitanum,

14.

1. Peneus caramote. 2. Stenopus spinosus.

3. Palaemon xiphias. 4. Gnathophyllum elegans.

5. Pagurus striatus (et Adamsia Eondelctii.) 6. Pagurus striatus.
7. Eupagurus Prideauxii (et Adamsia palliata.)

C. Mercaliano fee.

Werner t Winter, impr.

Aquarium Neapolitanum

1. Ilia nucleus.

3. Lambrus angulifrons.

5. Inachus scorpio.

C. Merculiano fee.

2. Pisa tetraodon.
4. Maja squinado.
6. Dorippe lanata.

Werner A Winter, impr.

Aquarium Neapolitanum,

16,

1. Calappa granulata.
3. Dromia fidgaris.
5. Lupa liastata.

C. Merculiano fee.

2. Pacliygrapsus marmoratus.
4. Eripliia spinifrons.
6. Carcinus maenas.

Werner & Winter, impr.

Aquarium Neapolitanum,

C. Merculiano fee.

1. Squilla mantis. 2. Gammarus.

3. Idotea hectica. 4. Phronima sedentaria.

5. Caprella. 6. Lepas anatifera.

7. Salamts perforatus.

Werner & Winter, impr.

Aquarium Neapolitanum,

18.

1. 2. Octopus vulgaris.

C. Merculiano fee.

Werner & Winter, impr.

Aquarium Neapolitanum,

19.

1. Argonaut a argo.
3. Loligo vulgaris.

2. Eledone moschata.
4. Sepia officinalis.

C. Merculiano fee.

Werner & Winter, impr.

Aquarium Neapolitanum,

20.

1. Haliotis tuberculata.

3. Cypraea pyrum.

5. Natica millepunctata.

7. Murex brandaris.

C. Mercnliano fee.

2. Patella caendea.

4. Cassis sulcosa.

6. Conns mediterranens.

8. Aporrhais pes pelecan'i.

Werner <t Winter, impr.

Aquarium Neapolitanum,

21

1. Tritonium cutaceum.
3. Dollam galea.

C. Merculiano fee.

2. Vermetus gigas.

4. Tritonium nodiferum.

Werner & Winter, impr.

Aquarium Neapolitanum,

22.

4.

1. Aplysia camelus. 2. Notarchus neapolitanus.

3. Gastropteron MecJcelii. 4. Pleurobranclius testudinarius.

5. Umbrella mediterranea.

C. Merculiano fee.

Werner A Winter, impr.

Aquarium Neapolitanum,

23.

2.

1. Doris tuberctdata. 2. Marionia quadrilatera.

3. Teihys leporina. 4. Aeolis papillosa.

5. Elysia viridis.

C. Mercaliano fee.

Werner <fe Winter, impr.

Aquarium Neapolitanum,

24.

1. Pterotracliea coronata.
3. Dentalium tarentinum.
5. Hyalaea triderdata.

C. Mercnliano fee.

2. Carinaria mediterranea.

4. Terebratula vitrea.

6. Tiedemannia neapolitana.

Werner A Winter, impr.

Aquarium Neapolitanum,

25.

1. Ostrea edulis.
3. Avicula hirundo.
5. Mytilus edulis.

C. Merculiano fee.

2. Pecten jacobaeus.

4. Pinna nobilis.

6. Lithodomus dactylus.

Werner A Wiator, impr.

Aquarium Neapolitanum,

26.

2.

1. Cardium aculeatum. 2. Solen vagina.

3. Venus verrucosa. 4. Tellina planata.

5. Donax trunculus. 6. Area barbata.

7. Solecurtus strigilatus. 8. Pholas dactylus.

9. Pectunculus glycimeris.

C. Merculiano fee. Werner <fe Winter, iinpr.

Aquarium Neapolitanum,

27,

s.

1. Phallusia mammillata.
3. Ciona intestinalis.
5. Fragarium areolatum.

2. Cynthia papillosa.
4. Diazona violacea.
6. Botryllus aurolineatus.

C. Merculiano fee.

Werner A Winter, impr.

Aquarium Neapolitanum,

28.

5.

1. Salpa maxima- a fricana 2a. et 2b. Salpa maxima-africana

(solitaria). (gregata).

3. Salpa pinnata (gregata). 4. Pyrosoma elegans.

5. Amphioxus lanceolatus.

C. Merculiano fee.

Werner <fe Winter, impr.

Aquarium Neapolitanum,

29.

1. Uranoscopus scaber.
3. Rhombus maximus.

C. Merculiano fee.

2. Trackings draco.
4. Solea vulgaris.

Werner A Winter, impr.

Aquarium Neapolitanum,

30.

Lophius piscatorius.

C. Merculiano fee.

Werner & Winter, impr.

Aquarium Neapolitanum,

31

1. Gobius capita. 2. Scorpaena porcus.

3. Blennius ocellaris.

C. Mercnliano fee.

Werner A Winter, impr.

Aquarium Neapolitanum,

32.

1. Trigla lyra.

3. Hippocampus guttulatus.

2. Dactylopterus volitans.
4. Syngnathus acus.

C. Merculiano fee.

Werner A Winter, impr.

Aquarium Neapolitanum,

1. Ophisurus serpens. 2. Conger vulgaris.

3. Muraena helena.

C. Merculiano fee.

Werner & Winter, irapr.

Aquarium Neapolitanum,

34.

.7.

1. Mugil cephalus.

3. Apogon rex mullorum.

2. Mulhis barb at us.
4. Xirichthis novacula.

C. Merculiano fee.

Werner A Winter, impr.

Aquarium Neapolitanum,

35.

1. Dentex vulgaris.
3. Oblada melanura.

C. Merculiano fee.

2. Pagellus erytlirinus.
4. Carax puntazzo.

Werner & Winter, impr.

Aquarium Neapolitanum,

36.

1. Serranus scriba. 2. Serranus gigas.

3. Serranus cabrilla.

C. Merculiano fee.

Werner & Winter, impr.

Aquarium Neapclitanum,

1. Labrus festivus.
3. Crenilabrus pavo.

C. Merculiano foe.

2. Labrus merula.
4. Umbrina cirrosa.

Werner & Winter, impr.

Aquarium Neapolitanum.

38.

1. Chrysophrys aurata. 2. Labrax lupus.

3. Corvina nigra.

C. Merculiano fee.

Werner & Winter, impr.

Aquarium Neapolitanum

1. Cantharus vulgaris. 2. Sox loops.

3. Box salpa. 4. Sargus amdaris.

5. Sargus Eondeletii.

C. Mereuliano fee. Werner & Winter, impr.

Aquarium Neapolitanum,

40,

2.

1. Alosa sardina. 2. Engraulis encrasichohis.

3. Pagrus vulgaris. 4. Maena vulgaris.

5. Smarts vulgaris.

C. Merculiano fee. Werner it Winter, impr.

Aquarium Neapolitanum,

41

1. Batistes capriscus.
3. Centriscus scolopax.

2. Capros aper.
4. Zeus faber.

C. Merculiano fee.

Werner & Winter, impr.

Aquarium Neapolitanum,

42.

3.

1. Lichia glauca. 2. Caranx trachurus.

5. Thynnus vulgaris.

C. Merculiano fee.

Werner <Sz Winter, impr.

Aquarium Neapolitanum,

43.

C. Merculiano fee.

1. Heliases chromis. 2. Julis vulgaris.

3. Julis turcica. 4. Motella vulgaris

5. Fierasfer acus (et Holothuria).

Werner A Winter, impr.

Aquarium Neapolitanum,

44.

1. Pristiurus melanostomus. 2. Mustelus laevis.

3. Scyllium catulus.

C. Merenliano fee. Werner & Winter, irapr.

Aquarium Neapolitanum,

45.

1. Centrina Salviani. 2. Squatina angelus.

C. Merculiano fee. Werner 4 Winter, impr.

Aquarium Neapolitanum

1. Trygon violaceus. 2. Torpedo ocellata.

3. Eaja asterias.

C. Merculiano fee. Werner & Winter, impr.

Aquarium Neapolitanum,

47.

Thalassochelys corticata.

C. Mereuliano fee.

Werner A Winter, impr.

THIS BOOK IS DUE ON THE LAST DATE
STAMPED BELOW

AN INITIAL FINE OF 25 CENTS

WILL BE ASSESSED FOR FAILURE TO RETURN
THIS BOOK ON THE DATE DUE. THE PENALTY
WILL INCREASE TO 5O CENTS ON THE FOURTH
DAY AND TO $1.OO ON THE SEVENTH DAY
OVERDUE.

1 1;

JUN 2 1947

4188*81

LD 21-100m-8,'34

244738